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Apex predators are vulnerable to environmental changes which can cascade through trophic levels of an ecosystem. Investigating prey‐predator relationships is important for directing conservation efforts and understanding how species may respond to ecosystem changes. This case study examined the diet and breeding success of the threatened powerful owl Ninox strenua in central Victoria where the box‐ironbark forests have undergone widespread clearing, fragmentation, and degradation. The powerful owl preys predominantly on arboreal mammals, however, some birds are also consumed. By analysing the contents of regurgitated owl pellets of two owl pairs, we found that birds comprised 29.3% of all prey items and contributed the largest proportion of prey biomass for one pair (34.4%). All mammalian prey species identified in the pellet remains are dependent on tree hollows, which are now a scarce and competitive resource in box‐ironbark forests. Despite consuming a diet lower in mammalian prey than found in other studies, breeding success over five consecutive years was 1.4 chicks fledged per pair per year, which is notably higher than historical observations in the region and similar to powerful owls in other parts of their distribution. Our observations suggest that flexibility in prey selection enables powerful owls to occupy ranges that have undergone significant ecosystem change. [ABSTRACT FROM AUTHOR]

Seabird reproductive success in northern latitudes is often linked with prey abundance, availability, size, or species. Causes are often broadly explained as changes in ocean currents/temperatures, or diets. Few studies trace diets down the food web to primary producers, thus missing what I propose as an underlying cause of seabird colony failure, dietary abundance of essential omega-3 polyunsaturated fatty acids (PUFA). PUFA differ from other nutrients because they are, in part, ligands—critical for reproduction and other physiological processes for the entire marine food web, not just for seabirds. Diatoms are one of the few life forms that can produce PUFA de novo , and a lack of PUFA in zooplankton and fish reduces their abundance and productivity, with consequences up the food web. Since the mid-1980s, historical prey of breeding seabirds has decreased, and frequency of colony failures has increased. In years of failure, prey often had less fat than historically preferred species. Likewise, proportions of alternate species' PUFA, from published papers, show lower values than in historical prey. Production of PUFA by diatoms is depressed in warmer and more acidic environments, and I hypothesize that these warmer and more acidic seas have affected production of PUFA over the past 3–4 decades. Assuming this is true, I propose that these lower amounts of PUFA have negatively impacted the breeding success of all members of the marine food web, not just seabirds. [ABSTRACT FROM AUTHOR]

Many industries are required to perform population viability analysis (PVA) during the consenting process for new developments to establish potential impacts on protected populations. However, these assessments rarely account for density‐dependent regulation of demographic rates. Excluding density‐dependent regulation from PVA‐based impact assessments is often assumed to provide a maximum estimate of impact and therefore offer a precautionary approach to assessment. However, there is also concern that this practice may unnecessarily impede the development of important industries, such as offshore renewable energy.In this study, we assess density‐dependent regulation of breeding success in 31 populations of seabird. We then quantify the strength and form of this regulation using eight different formulations. Finally, we use PVA to examine how each formulation influences the recreation of observed dynamics (i.e. model validation), as well as the predicted absolute and relative population response to an extrinsic threat (i.e. model projection).We found evidence of both negative (n = 3) and positive (n = 5) regulation of seabird breeding success. In populations exhibiting negative regulation, excluding density‐dependent regulation from PVA‐based impact assessment allowed uncontrolled population growth, such that model outcomes became biologically implausible. By contrast, in populations exhibiting positive regulation, excluding density‐dependent regulation provided an appropriate reconstruction of observed dynamics, but population decline was underestimated in some populations. We find that multiple formulations of density dependence perform comparably at the detection, validation and projection stages of analysis. However, we tentatively recommend using a log‐linear or Weibull distribution to describe density‐dependent regulation of seabird breeding success in impact assessments to balance accuracy with caution. Finally, we show that relative PVA metrics of impact assessment cannot necessarily be used to overcome PVA misspecification by assuming density independence in positively regulated populations.Synthesis and applications: We suggest that a density‐dependent approach when performing PVA‐based assessments for seabird populations will prevent biologically unrealistic, unconstrained population growth and therefore ensure meaningful PVA metrics in populations experiencing negative regulation. It will also maintain a precautionary approach for populations experiencing positive regulation, crucial when estimating impacts for these more vulnerable populations. These conclusions have immediate international application within the consenting processes for marine industries. [ABSTRACT FROM AUTHOR]

The frequency of extreme climatic and weather events has increased since 1950 due to global changes induced by human influence. These events can have significant impacts at the individual, population, and community levels across various taxonomic groups. They can be particularly detrimental to bird populations during their breeding season, affecting specific breeding parameters. This study originated from an exceptionally rare breeding season of a resident Great Tit population recorded in spring 2002 when an unusual mortality of nestlings was observed. We quantified weather conditions (temperature, rainfall) from the end of April, a few days before we started detecting failed nests, and compared them with previous and subsequent years. In early May, when many pairs were incubating or caring for newly hatched chicks, we detected unusually low ambient temperatures and unusually high rainfall. This event likely caused that many first clutches failed completely, and that, compared with previous and subsequent years, fledging and breeding success was relatively low in those which were successful. There was also an increased proportion of replacement clutches that year. Anyway, the overall production of fledglings per breeding pair over the breeding season was 2.39, lower than other years. Although recruitment rate in 2003 was similar to other years, the lower production of fledglings in 2002 probably resulted in a decrease in the number of breeding pairs in the following years. [ABSTRACT FROM AUTHOR]

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Simple Summary: We studied the survival of young Indian leopard cubs in the Jhalana Reserve Forest, India, during their first two years of life. Using data from trail cameras collected over four years (2018–2021), we calculated survival rates with a statistical method to identify when cubs are most at risk. All adults and cubs included in this study were identified at the individual level based on the rosette patterns on their flanks and their facial markings. We found that during the first year, the survival rate of the cubs was about 74%, indicating that this period is particularly challenging for their survival. In the second year, the survival rate improved to around 83%, showing that the cubs are more likely to survive as they grow older. Overall, 61% of the cubs survived in our population to become independent after two years of parental care. These findings are important for creating effective conservation strategies to protect leopard cubs in fragmented habitats. We investigated the survival of cubs in a wild Indian leopard (Panthera pardus fusca) population in the Jhalana Reserve Forest (JRF), India. The research focuses on analyzing the survival of leopard cubs during their first two years of life. Survival functions were estimated using the Kaplan–Meier method based on data collected with trail cameras over four years from 2018 to 2021. We found that the mean survival probability of cubs during the first year of life was 0.739, indicating that this period is particularly challenging for their survival. In the second year, the survival probability increased to 0.831, reflecting an improvement in survival as the cubs grew older. The combined survival rate over the two-year period, calculated as the product of the first- and second-year survival rates, was 0.618. These findings highlight the critical periods in the early life stages of leopard cubs, which are essential for developing effective conservation strategies in fragmented habitats to enhance their survival. [ABSTRACT FROM AUTHOR]

Asian hornbills have limited ex situ breeding success, yet these species are some of the most threatened of birds, in need of managed breeding programs. To optimize breeding and increase the sustainability of such populations, it is necessary to assess and improve their husbandry and welfare. Evidence to improve reproduction can be gathered through global husbandry surveys. A survey was sent out to all European Association of Zoos and Aquaria and Association of Zoos and Aquarium holders of the wreathed hornbill (Rhyticeros undulatus) and Papuan hornbill (R. plicatus) to determine predictors for ex situ breeding success. This research found that pairs that have spent more years together (p =.016) and that adding additional proteins to the diet (p =.006) are two significant predictors of breeding success for wreathed‐ and Papuan hornbill pairs. This paper found a general trend that successful hornbill pairs prefer nest boxes that are situated outside (p =.054). The behaviors of calling to each other and sitting in close proximity showed a general trend and were observed more frequently in successful pairs and, therefore, could be good indicators of bonded pairs. We recommend that ex situ institutions allow their hornbill pairs time to form strong bonds, and that pair compatibility is monitored regularly to ensure that such interactions are positive and not consistently negative. An increase in the percentage of dietary proteins, prior and during the breeding season appears to stimulate pairs to breed. If the management and husbandry alterations presented in this study are implemented, the sustainability of Rhyticeros hornbill populations may be enhanced. Research highlights: Hornbills are difficult to breed in captivity.A husbandry survey revealed that dietary proteins and strong pair bonds influence breeding success.Future studies should focus on behavioral outputs and nest box characteristics and parameters. [ABSTRACT FROM AUTHOR]

More than 40 hypotheses predict associations between features of nest architecture and at least one measure of reproductive success. However, quantitative studies of reproductive consequences of nest characteristics remain scarce. In addition, most studies were conducted on model species of which nests can be easily monitored with artificial nest-boxes. Here, we review the replicability of research protocols and findings in model species, with many repeat studies focusing mainly on nest-size components, animal-derived nest material, or fresh greenery in model species of secondary hole-nesting birds: Blue Tits (Cyanistes caeruleus), Great Tits (Parus major), Tree Swallows (Tachycineta bicolor), and Starlings (Sturnus spp.). The studies looked for correlations between nest traits and aspects of breeding performance that can be easily quantified in the field, such as clutch size, brood size at hatching or fledging, the percentage of eggs that hatch or fledge, or nestling characteristics assumed to reflect qualities associated with survival probabilities (e.g., morphometry, body condition, blood profiles). We discuss the consequences of poor replicability of research methodologies and provide explanations for why many of these studies reported poor associations between nest design and breeding success at different spatiotemporal scales. We also make suggestions for future research.

Monitoring programs are pivotal to establishing sound management. Due to economic, logistic, and time limitations, monitoring programs often overlook differences among life‐history stages. However, species occurrence does not necessarily mean population viability, and it is unclear to what extent monitoring programs that do not consider separately adult presence and reproduction provide effective management indications. Unfortunately, collecting data on certain life stages requires high sampling effort, leading to a trade‐off between model reliability and resources needed for monitoring. We collected data on presence and reproduction of amphibians by monitoring 207 waterbodies in Lombardy (northern Italy) in 2017–2022. We then used multistate occupancy models to test whether certain environmental features, namely, pond area, hydroperiod, forest cover, shade, aquatic vegetation, and predators’ presence, differentially affected adult occurrence and breeding probabilities of multiple amphibian species. To assess optimal sampling efforts, we modeled the detection probabilities of adults and reproduction across multiple species. Finally, we identified the optimal monitoring strategy under different scenarios of resource availability, comparing adult‐only monitoring versus joint assessment of the occurrence of adults and reproduction. In many cases, the main drivers of adult occurrence and reproduction did not coincide because most investigated ecological variables affected one life stage or the other. Forest area, for instance, increased occurrence probabilities of adults of the endemic Rana latastei but showed no effect on their reproduction probabilities. Quantitative estimates of the sampling effort showed that occurrence of adults was easier to spot in 4 out of 7 species. Multicriteria decision analyses showed that when resources were scarce, monitoring adults was the optimal strategy for those 4 species. Conversely, with more resources, monitoring both adults and reproduction emerged as the best strategy for all the considered species. Integrated monitoring of adults and reproduction is essential to comprehensively identify effective conservation measures for amphibians. [ABSTRACT FROM AUTHOR]

Determining the effectiveness of conservation actions is a priority in conservation biology, especially in island ecosystems which can host large numbers of endemic and often threatened species. In this study, we have brought together a genetic, body condition and breeding success assessment with the aim of evaluating the viability of a newly founded population of the endangered Gran Canaria blue chaffinch (Fringilla polatzeki), the forest passerine species with the most restricted distribution in the Western Palearctic. The species occurs exclusively in the Canary pine forests (Pinus canariensis) of the island of Gran Canaria, with the Inagua nature reserve harbouring the highest number individuals. In 2010, a translocation program was initiated within the same island in the nearby pine forests of La Cumbre with the goal of establishing a viable breeding population. Genetic results revealed that La Cumbre shows genetic parameters (diversity, inbreeding, and relatedness) similar to the core source of Inagua, which contrasts with the reduced genetic diversity expected due to the small size of the newly founded population. The biometric and body condition results (wing and tarsus length, body mass, and length asymmetry of the tail feathers), together with the breeding success (nest survival and number of fledglings per successful breeding attempt), were also similar in both populations. Overall, these findings suggest that the translocation program has been successful and provide insights on the effectiveness of the actions performed. Our evaluation also delivers future avenues for the conservation planning in other upland forest endangered avian species inhabiting island ecosystems, especially those threatened by the effects of global warming. [ABSTRACT FROM AUTHOR]

Context: As complementary terrestrial and aquatic habitats are pulled apart by environmental change, animals will have to adjust their behaviours to successfully track their fundamental niches. We introduce a novel example of how climate change impacts can drive separation between complementary foraging and breeding habitats in seabirds. Objectives: We evaluated how Black Noddies (Anous minutus) modified their movement behaviour across the seascape to access complementary habitat types during a period of local food scarcity; and whether this influenced their breeding success. Methods: We quantified characteristics of foraging behaviour relating to energy consumption (time, distance and area covered) over four breeding seasons for Black Noddies (A. minutus) and compared favourable years (2019, 2020 and 2021) to an unfavourable year (2022). We also quantified and compared chick health and survival rates over the same period. Results: In 2022, severe reduction in local food abundance on Heron Island led breeding Black Noddies to forage further by an order of magnitude, utilizing a remote wooded island (Bushy Islet) as an overnight roosting location. This was a novel and completely unexpected response to the altered environmental conditions. At the same time, 2022 saw significant increases in chick mortality and decreases in chick health compared to other years. Conclusions: We show how a growing mismatch between nesting, roosting, and foraging sites pushed individuals in a breeding tropical seabird population to extend their foraging range by an order of magnitude, with direct negative consequences for juveniles. Our findings highlight the need to explicitly consider habitat complementation in land- and seascape conservation initiatives and planning. [ABSTRACT FROM AUTHOR]

Shorebirds are facing global decline as a consequence of anthropogenic effects that include habitat loss, increased predation and climate change. Although some shorebirds are extensively studied, basic data on life history, ecology and behaviour are still lacking especially for populations where climate change is expected to have severe effects. Here, we provide the first detailed investigation of a high-altitude nesting shorebird in the Qinghai–Tibetan Plateau, the Tibetan Sand Plover Charadrius atrifrons. This alpine-breeding Central-Asian species recently split from the Lesser Sand Plover Charadrius mongolus that breeds in Eastern Siberia. Understanding the fundamental ecology and behaviour of alpine-breeding shorebirds is important for predicting the challenges these high-altitude species will face given the human-driven environmental changes that are likely to take place in these habitats. Here, we show that Tibetan Sand Plovers in the Qinghai–Tibetan Plateau have a short breeding season from mid-May to late-June, and exhibit social monogamy and bi-parental care of the clutch. Since they have low hatching success (18 of 57 nests hatched) and no chance of renesting, maintaining population size in the future may pose a challenge. To provide essential information for protection of this species in a vulnerable habitat, further demographic studies are warranted to better understand how climate change will mould adaptations of this specialised high-altitude species to their environment. [ABSTRACT FROM AUTHOR]

Monitoring of breeding success in wildlife is key for evaluating population trends and support conservation measures. However, it is challenging depending on breeding places or non-accessible habitat. In recent years, new technologies were applied to studies of bird biology, i.e. drones. UAV (drones) are available to study new aspects of bird ecology, which are not available using traditional methods. The Raven Corvus corax predominantly nests in upper tree canopies or on high cliffs. Hence, it is challenging to monitor it breeding success from the ground. Our study were conducted in forests in NE Poland, on the 77 arboreal Raven nests in 2021–2022. By using drones, we investigated (i) whether the classic data on breeding success from ground observations differ from those of nest inspections via drone, and (ii) to what extent the adult birds behave when the drone is used at the nest. The inspection from the ground failed to determine the contents of as many as 30% of the occupied nests. Inspections using a drone and those made from the ground yielded different results, as aerial assessment showed a higher number of the young (respectively 1.93 vs. 3.22 per successful brood). Broods with three young accounted for 6.5% of nests controlled from the ground and 23.3% using a drone, while broods with two young accounted for 33.8% and 10.4% of nests, respectively. During most of the inspected nests (65% of the cases), adult birds sat nearby in the tree tops and called. In 12% of the cases, the birds flew close to the nest, passing the drone at a distance of more than 20 m, and did not attempt to approach the device. In four cases, adult birds closed the drone at less than 10 m. A direct collision did not happen. The most vital reactions were recorded in several instances (only 4.2%) in which the birds were not near the nest when the inspection began but arrived during the inspection. Drone surveys have revealed previously un-described behavior of birds, alarmed at the examination of empty nests. In 50 nests, 65% of the cases, the Raven tolerated the drone's presence at the nest, although the birds showed concern and occasionally defensive reactions. It seems that the adverse reaction of birds is weaker when they associate the appearance of a drone with human presence. Key recommendations: control in teams of two - operator and observer, starting end landing in close vicinity of the nest tree, immediate interruption of flight if birds react, forbade flying directly over the nest. It is advisable to check the reaction of adult Ravens to drone inspections of nests with small nestlings. To sum up, our study showed that the drone inspections did not harm the adult birds but provides a more reliable data for reproduction than the observation from ground. [ABSTRACT FROM AUTHOR]

Lapwing are among those ground nesting bird species that suffered strong population declines following agricultural intensification in many parts of Europe. The key problem appears to be a low breeding success which, depending on the situation, may be due to predation of eggs and chicks, starvation of chicks especially during dry conditions, agricultural activities leading to direct killings, and suboptimal breeding habitat. Here, we report on a population of 40–60 lapwing breeding pairs in an intensively cultivated arable landscape in central Switzerland, where protection from farming activities, implementation of special lapwing habitat and nest fencing to exclude terrestrial predators (mainly red fox) started in 2005 and is still ongoing. Chicks were ringed and families subsequently observed every 2–3 days. Hatching success for fenced nests built before May was high. Low hatching success was observed in unfenced nests due to high predation rates and in late nests due to abandonment by the female when the vegetation was growing too tall (e.g. maize). Regularly, chicks disappeared during the night shortly after hatching. Most likely many of them first left the fence and were predated outside. Our observations from a fenced field with wet soils and puddles suggest that lapwing may produce sufficient offspring if predation can be reduced and if large enough areas with suitable habitat are available. [ABSTRACT FROM AUTHOR]

A robust understanding of the mechanisms driving demographic change in wild animal populations is fundamental to the delivery of effective conservation interventions. Demographic change can be driven by variation in adult survival, recruitment of juveniles into the breeding population or breeding productivity – the number of fledglings produced per breeding pair. Across Europe, low breeding productivity in wader populations has been a significant driver of population decline, increasing the importance of gathering accurate data on breeding productivity. Monitoring wader breeding productivity is challenging because finding nests can be time‐consuming and requires experienced fieldworkers; wader chicks are nidifugous and difficult to count due to their cryptic behaviour; and waders often have high re‐laying rates following nest failure, meaning that hatching or fledging can be highly asynchronous. This paper reviews approaches to estimating breeding productivity where fieldworkers either record the agitation or alarm‐calling behaviour of adults with dependent young, make direct observations of broods on survey visits, or both. Using a systematic literature search (restricted to Europe where most of these studies have taken place) we identified 38 peer‐reviewed papers which used this approach. The productivity metrics produced can be divided into the following categories: (i) 'Hatching Success' (HS), (ii) 'Fledging Success' (FS) and (iii) 'Young Fledged Per Pair' (YFP), from the coarsest to the most precise. The first two metrics are most often used when direct observations of broods are not possible due to the behaviour of broods or vegetation structure; YFP is preferred if brood counts are possible. Design of an appropriate metric depends on (i) whether accurate brood counts are possible; (ii) whether adults exhibit diagnostic agitation behaviour when young are present; (iii) whether individual breeding territories are separable; (iv) whether re‐nesting rates are assumed to be high; and (v) the availability of experienced surveyors (particularly where behavioural observations are required). Globally there are many wader species for which the methods described here could provide valuable information and we hope this review encourages further development or adoption of these methods. [ABSTRACT FROM AUTHOR]

Vertebrate populations are often monitored as part of broader assessments of ecosystem status, where they are expected to provide information on the ability of the ecosystem to support higher‐level predators. However, because many vertebrates are long‐lived and often only subsets of their populations can be monitored, abundance may not be sufficiently responsive to ecosystem status to provide early warnings of impending changes. Marine birds are often used as indicators of ecosystem status but, due to their long lifespan and delayed recruitment to the breeding population, changes in abundance are generally slow and often difficult to interpret. Their breeding productivity is, however, also widely monitored and much more responsive to ecosystem status, but the relevance of variation in productivity may be difficult to assess. We propose a model‐based indicator that integrates monitoring of abundance and breeding productivity through demographic matrix models. The metric of the proposed indicator is the expected population growth rate, given the observed level of breeding productivity. This expected growth rate is then compared with a threshold derived from the criteria employed for red‐listing of threatened species by the International Union for the Conservation of Nature. We demonstrate the suggested approach using data from Black‐legged Kittiwakes Rissa tridactyla in the Greater North Sea region, Northwest Europe. The proposed indicator shows that the current level of breeding productivity is expected to lead to a population decline of 3–4% per year, which is equivalent to a red‐list status as Endangered for the species in this region. Our indicator approach is used in OSPAR's Quality Status Report 2023 and is expected to be used by European Union member states for reporting under the Marine Strategy Framework Directive in 2024. Our approach represents a major step forward in assessing the status of marine bird populations; the ideal next step would be to develop a coherent Integrated Population Modelling (IPM) framework that would allow inclusion of all data on population abundance and demography collected across the large and diverse marine ecosystems involved. [ABSTRACT FROM AUTHOR]

Introduction: Seabirds and other insular birds are an important part of marine ecosystems and are increasingly threatened worldwide. Phenology, abundance, distribution, and breeding success are important baseline parameters needed to evaluate population trends and dynamics, identify biodiversity hotspots and potential breeding sites, and assess habitat selection. In the Red Sea basin, reliable and complete data on birds are lacking for islands in most of the Important Bird Areas (IBA). Such data are now especially important since development projects have started at several of these locations. Here, we assess the distribution, abundance, phenology, and population trends of 13 bird species that breed in the Duba Islands, Al Wajh Bank, and Al Lith Islands. Breeding success and habitat selection for six species were also assessed. Methods: Between December 2020 and August 2023, more than 90 islands were visited multiple times with different frequencies. All nests were counted, and the area occupied by the different colonies was georeferenced. Breeding success was assessed by visiting selected colonies multiple times until the chicks were ready to fledge. Habitat selection was determined by analyzing the habitat found in the georeferenced colonies. Results: More than 25,000 nests were counted each year, mainly in the summer, on more than 75 islands. Of the 13 species studied, the most abundant and widespread species was the White-cheeked tern, and the second most widespread was the Osprey. Discussion: We estimate that the Al Wajh Bank hosts the following percentages of global breeding populations: Crab plover: 5%, Sooty gull: 17%-35%, White-eyed gull: 15%, Bridled tern: 1%, White-cheeked tern: 4%, and Lesser crested tern: 2%, making the area a regional and global hotspot for these species. Some of the islands occupied by breeding birds are slated for development for tourismactivities as part of the Kingdom's tourism expansion plans. At the same time, there are several ambitious conservation programs underway in these areas. To be effective, such programs require reliable and comprehensive data of the kind presented here. [ABSTRACT FROM AUTHOR]

Simple Summary: For decades, numerous hypotheses have been suggested to explain why nest characteristics should be associated with reproductive success. However, quantitative intraspecific studies of associations between variations in nest architecture and breeding success remain rare, and they are most often conducted on model species of which nests can be easily monitored with artificial nest-boxes. Here, we review the published literature dealing with the reproductive consequences of nest design in the best-studied secondary-cavity-nesting bird species. We show that research protocols and findings are often poorly replicated across repeat studies. We discuss why many field studies report weak associations between nest architecture characteristics and breeding success and propose suggestions for future research directions. More than 40 hypotheses predict associations between features of nest architecture and at least one measure of reproductive success. However, quantitative studies of reproductive consequences of nest characteristics remain scarce. In addition, most studies were conducted on model species of which nests can be easily monitored with artificial nest-boxes. Here, we review the replicability of research protocols and findings in model species, with many repeat studies focusing mainly on nest-size components, animal-derived nest material, or fresh greenery in model species of secondary hole-nesting birds: Blue Tits (Cyanistes caeruleus), Great Tits (Parus major), Tree Swallows (Tachycineta bicolor), and Starlings (Sturnus spp.). The studies looked for correlations between nest traits and aspects of breeding performance that can be easily quantified in the field, such as clutch size, brood size at hatching or fledging, the percentage of eggs that hatch or fledge, or nestling characteristics assumed to reflect qualities associated with survival probabilities (e.g., morphometry, body condition, blood profiles). We discuss the consequences of poor replicability of research methodologies and provide explanations for why many of these studies reported poor associations between nest design and breeding success at different spatiotemporal scales. We also make suggestions for future research. [ABSTRACT FROM AUTHOR]

Implementing effective, affordable and ethical conservation management will be crucial for minimising future biodiversity losses. Such management requires reliable foundational evidence to help managers make informed choices about how to address the needs of their target species. Unfortunately, such evidence is still lacking for many species and management scenarios.One major global challenge is improving the reproductive success of threatened species in the context of predation. We conducted a systematic review and meta‐analysis of in situ experiments that used non‐lethal methods to protect bird nests against predators, with the aims of summarising global trends in nest protection efforts, comparing the effectiveness of different protection measures and informing future research and management. We considered peer‐reviewed studies in English.We detected a large geographic and taxonomic bias in the evidence base with 58% of articles conducted in North America and 76% on ground‐nesting birds. Less than 3% of articles involved taxa listed as Endangered or Critically Endangered and 51% of study units lasted just a single breeding season.Nests protected with exclosures, fences and guards were more likely to be successful than their unprotected controls. Interventions involving deterrents, conditioned taste aversion, chemical camouflage and diversionary feeding did not have a significant positive effect on nest success, but the interventions in these categories were less common and more diverse in nature.Synthesis and applications. To increase their conservation value, future non‐lethal nest protection experiments should whenever possible clearly state overall aims, take place over multiple seasons, use a comparable control and test non‐lethal protection methods independently of lethal predator control. Greater focus is required on under‐studied taxa such as cup‐nesting songbirds and birds in South America, Africa and Asia, and novel protection techniques such as deterrents and chemical camouflage. Practitioners should consider the evidence we synthesise here when deciding whether non‐lethal nest protection approaches are optimal for their study system, to increase conservation success and reduce ethical and financial costs. [ABSTRACT FROM AUTHOR]

The Pacific Coast population of the western snowy plover (Anarhynchus nivosus nivosus) is a federally threatened species and is a California Species of Special Concern. Knowledge about their nest site selection requirements is important to this species’ management in the San Francisco Bay area. We measured the percentage of sand, percentage of crushed oyster shells, number of shells, and total shell surface area for 56 nests of western snowy plover at the California least tern (Sternula antillarum browni) colony in Hayward, California, USA, over a 14-year period (2008–2021). Using pairwise t-tests, we compared these measurements to those obtained from 56 randomly chosen non-nest sites. Results indicated that plovers select nest sites with greater oyster shell metrics than paired random sites. The contrast in the shell-related nest metrics (i.e., the difference between the nest site and the paired site) showed significant positive relationships with both hatching success and number of fledglings using linear regression analysis. These results, supporting federal species recovery, suggest that the western snowy plover may improve their nesting success through oyster shell enhancement, which may provide more camouflage for the eggs and chicks than locations with fewer shells.

ABSTRACT Experiments with artificial nests are widely used to gain insights into the behavioral and ecological factors affecting the survival of natural nests. Undesired effects on nest success may arise from variations in nest and egg characteristics (e.g., dimensions, texture, and color). Still, evaluating these potential factors is seldom considered in the design of artificial nest studies, particularly in tropical regions. We assessed the effect of two nest types (cup-shaped and dome-shaped) and two egg types (differing in size and color) on the survival of artificial nests. The egg types included smaller (22-25 mm), variously colored eggs of blue-breasted quails, Synoicus chinensis (Linnaeus, 1766) and larger (25-30 mm), white-spotted-with-brown eggs of Japanese quails, Coturnix japonica Temminck & Schlegel, 1848. The experiment took place within a coastal shrubland (restinga) in southeastern Brazil, from August 16-31, 2017. This period coincides with the onset of the breeding season for most insectivorous bird species in the region. The nests were observed for 15 days to assess predation, revealing higher survival rates in dome-shaped nests than cup-shaped ones. Egg type, however, did not affect survival rates. This suggests that coastal shrubland nest survival is influenced by factors seen in other Neotropical environments, where dome-shaped nests are likewise less vulnerable to predation. Interestingly, egg color and size did not impact nest predation in this environment. We suggest that future studies on artificial nests should incorporate variations in nest types and validate the selection of egg types.

Abstract Background GPS-transmitters enable detailed study of animal behaviour but may impact the animals. Impacts vary from short-term stress and habituation to longer-term effects on e.g., migration and reproduction. To study impacts, ideally, true controls (i.e., uncaptured or untagged animals) are used, but unbiased assessments of their migration timing and breeding performance are challenging, especially in remote areas. Alternatively, quasi-controls can be used: individuals tagged longer ago, or the same tagged individuals but in later years. Quasi-controls reveal tagging effects that differ between the first and following years. Results We captured Pink-footed geese (Anser brachyrhynchus) in spring and summer and deployed GPS-transmitter neckbands. In spring, geese were caught with cannon or clap nets on stopovers in Norway and Finland, 2 weeks before departure to breeding areas in Svalbard and Novaya Zemlya. In summer, geese were rounded up during wing moult in Svalbard. First, we compared geese tagged recently in spring with geese tagged in spring or summer 1–4 years prior. Newly tagged geese migrated significantly later, by 2 days, than previously tagged geese, both at departure from the spring stopover and arrival to the breeding grounds, while migration duration did not differ. Breeding propensity and laying date did not differ, but nesting success tended to be lowered, resulting in a significantly lower annual probability to produce hatchlings in recently tagged geese than in previously tagged geese. Second, within individuals tagged in spring, spring migration advanced in their next year, suggesting delay in their first spring. This was likely not an ageing effect, as geese tagged in summer showed no advancing spring migration timing over the years. Third, in Svalbard, observed brood sizes of geese tagged in summer and untagged geese did not differ 1 year after tagging. Conclusions The capture and GPS-tagging of geese 2 weeks before spring departure delayed their spring migration and lowered their probability to produce hatchlings in that year. These effects lasted longer than previously reported week-long effects of GPS-tagging on time budgets in summer and of neck-banding on spring body condition. Additional study is needed to evaluate longer-term or permanent effects which remain undetected with quasi-controls.

Nestlings normally exhibit a mix of traits that attract parental care, such as postural and vocal begging and carotenoid‐based mouth colouration. These signals are hypothesised to be signs of nestling needs (vocal begging) and quality (mouth colouration). Therefore, we hypothesised that broods, where nestlings beg for less time and display more saturated carotenoid‐based mouth colouration, would have lower nestling mortality. We tested these predictions in two wild blue tit (Cyanistes caeruleus) populations. The breeding success (here defined as the proportion of eggs that produced fledglings) was related to nestling mouth flanges' carotenoid‐based colour saturation. This means that blue tits that raised nestlings with more coloured flanges had a higher within‐population breeding success. Time spent in vocal begging, by contrast, was not associated with breeding success. Hence, our findings reveal that some communication signals displayed by nestlings (carotenoid‐based colouration) predict breeding success, in our study mostly reflecting the proportion of eggs that hatched, while begging intensity does not, probably because the former reflects a better maternal pre‐laying condition and nestling physiological status in the mid‐term. [ABSTRACT FROM AUTHOR]

According to the 'selfish herd' hypothesis, most seabird species breed colonially so that individuals can decrease their risk of predation by forming compact groups. However, costs and benefits associated with colonial breeding may not be evenly distributed among individuals within a colony. At Adélie penguin colonies, individuals nesting on the periphery of subcolonies (distinct groups of nests) may experience higher rates of nest predation by south polar skuas, and thus the optimal aggregation pattern for Adélie penguins may be within groups that minimize the proportion of edge nests. Nevertheless, some penguins choose to nest solitarily, at significant distances from conspecifics. We tracked 50 of these "solitary-nesting" Adélie penguins at Cape Crozier, a large colony on Ross Island, during the 2021 nesting season and compared their breeding success to individuals nesting within subcolony boundaries. We found that both solitary and subcolony nests successfully raised chicks large enough to join crèches and left unattended by adults. However, chicks from solitary nests exhibited a rate of mortality more than six times higher during the transition from nest brooding/guarding to crèche stage. In the 2022 nesting season, we found that solitary nests which had previously hosted actively breeding penguins were more likely to be re-occupied. Solitary nesting therefore appears to be a less-successful alternative to breeding within subcolonies, but enough individuals could be successful with this approach to maintain the apparently disadvantageous behavior and effectively pioneer previously unused locations, possibly including eventual new colony locations. [ABSTRACT FROM AUTHOR]

Background: GPS-transmitters enable detailed study of animal behaviour but may impact the animals. Impacts vary from short-term stress and habituation to longer-term effects on e.g., migration and reproduction. To study impacts, ideally, true controls (i.e., uncaptured or untagged animals) are used, but unbiased assessments of their migration timing and breeding performance are challenging, especially in remote areas. Alternatively, quasi-controls can be used: individuals tagged longer ago, or the same tagged individuals but in later years. Quasi-controls reveal tagging effects that differ between the first and following years. Results: We captured Pink-footed geese (Anser brachyrhynchus) in spring and summer and deployed GPS-transmitter neckbands. In spring, geese were caught with cannon or clap nets on stopovers in Norway and Finland, 2 weeks before departure to breeding areas in Svalbard and Novaya Zemlya. In summer, geese were rounded up during wing moult in Svalbard. First, we compared geese tagged recently in spring with geese tagged in spring or summer 1–4 years prior. Newly tagged geese migrated significantly later, by 2 days, than previously tagged geese, both at departure from the spring stopover and arrival to the breeding grounds, while migration duration did not differ. Breeding propensity and laying date did not differ, but nesting success tended to be lowered, resulting in a significantly lower annual probability to produce hatchlings in recently tagged geese than in previously tagged geese. Second, within individuals tagged in spring, spring migration advanced in their next year, suggesting delay in their first spring. This was likely not an ageing effect, as geese tagged in summer showed no advancing spring migration timing over the years. Third, in Svalbard, observed brood sizes of geese tagged in summer and untagged geese did not differ 1 year after tagging. Conclusions: The capture and GPS-tagging of geese 2 weeks before spring departure delayed their spring migration and lowered their probability to produce hatchlings in that year. These effects lasted longer than previously reported week-long effects of GPS-tagging on time budgets in summer and of neck-banding on spring body condition. Additional study is needed to evaluate longer-term or permanent effects which remain undetected with quasi-controls. [ABSTRACT FROM AUTHOR]

Investigator disturbance while monitoring seabirds can result in lower survival rates and breeding success, leaving lasting negative impacts on the population and biasing observations. For example, monitoring rhinoceros auklets (Cerorhinca monocerata) and other burrowing alcids can reduce breeding success or even survival through handling stress and damage to nesting habitat. For this reason, researchers must seek to decrease colony disturbance. Automated radio-frequency identification (RFID) via passive integrated transponder (PIT) tags is an inexpensive and reliable way to identify individual presence and record attendance behaviour, avoiding the need to recapture seabirds or visit the colony frequently. PIT tags either can be implanted subcutaneously or attached externally to leg bands, but it is unclear which method causes lower disturbance. To examine the impact of PIT tagging on rhinoceros auklets nesting in artificial burrows on Middleton Island, Alaska, we monitored burrow entrances with automated recording RFID readers to collect presence and nest attendance data. PIT-tagged (either band attachment or subcutaneous implant) and control birds had similar breeding success and chick growth rates. Breeding success was similar between nests with one or two parents marked. Birds tagged externally were detected less often than birds marked with a subcutaneous implant. We conclude that PIT tagging of rhinoceros auklets is a relatively non-invasive method for seabird monitoring, and that subcutaneous implants do not cause more disturbance than external attachment. [ABSTRACT FROM AUTHOR]

Knowledge of the relationships between food habits and habitat is crucial for the assessment of habitat quality for birds. The present study investigated the diet and reproductive success of Little Bitterns Ixobrychus minutus nesting on cyprinid fish ponds, an important breeding habitat of this species in central and eastern Europe. Being subject to different management practices, fish ponds provide food resources of uneven availability for this small heron. Prey items regurgitated by nestlings were examined, and breeding success was estimated on monoculture ponds stocked either with small fish (of a size suitable for feeding nestlings) or large fish (unavailable to Little Bitterns and adversely affecting their non-fish prey), on abandoned ponds dominated by small fish but with large fish also present, and on angling ponds dominated by large sport fish but harbouring significant numbers of small fish as well. A total of 1356 prey items from 78 broods were identified. Although Little Bitterns exhibited dietary flexibility in response to the contrasting availability of prey on their nesting ponds, the bulk of the nestlings' diet consisted of fish. The size of fish brought to the nest increased significantly with brood age, showing that parents adjusted the prey size to the gape constraints of their young. The chick production determined for 73 broods did not differ with respect to pond management, but the dietary composition indicated that to compensate for food shortages, birds nesting on ponds containing mainly large fish made foraging flights to food-richer ponds. The abundance of small-sized fish prey may be a factor limiting the breeding success of small- and medium-sized predatory waterbirds and should be taken into consideration in management strategies of habitats dominated by fish. [ABSTRACT FROM AUTHOR]

Plumage ornaments of birds, both pigment-based and structural, are considered age or condition-dependent, honestly signalling male quality, sexually selected traits, influencing the variation in breeding performance as well as adaptive sex allocation. In the present study, we examine the effect of age of males on the plumage structural colour in Common Kingfisher, and evaluate the breeding output (laying date, total number of young per breeding season, mean number of young per nest, total number of broods) and sex ratio in relation to two ornamental traits (forehead and rump structural colour). During the three years 2016–2018 in the Danube river system (south-western Slovakia), we collected data from 49 males, 102 broods and 645 nestlings. Our data demonstrate that structural colour is a condition-related and age-sensitive signal, while males with increased weight expressed less saturated blue forehead feathers, and old males displayed more saturated cyan rump feathers than young ones. Moreover, the brood sex ratio varies with male coloration in an age-dependent manner. The plumage colour of young males did not affect the brood sex ratio, whereas old males with increasing intensity of cyan rump had more sons than duller ones. Neither single ornamental trait nor age predicted breeding output of kingfisher males. Nevertheless, our results indicate that the blue structural plumage of kingfisher males may serve as an indicator of age and a certain kind of quality with a consequence on adaptive sex allocation in this species. [ABSTRACT FROM AUTHOR]

Simple Summary: The decline in biodiversity in agricultural areas in much of biological Europe is linked to agricultural intensification and land use changes. Bird species inhabiting natural and semi-natural grassland are among the most endangered ecological groups in Europe. This study aimed to determine the impact of grassland use on the availability of arthropods for red-backed shrike Lanius collurio and the condition of their chicks. A total of 133 pastures with different types of use were delineated: 1. extensively used meadows, 2. intensively used meadows fertilised with mineral fertilisers, and 3. intensively used meadows fertilised with manure. The analyses also took into account environmental factors that can affect food availability and condition parameters of chicks (distance to the forest, distance to the river, soil moisture, and proportion of shrubs and tree stands in the meadow border zone). The diversity of arthropods was greatest in extensively used meadows, and the average abundance and proportion of invertebrates over 1 cm in length was highest in intensively used meadows, especially those fertilised with manure. Coefficients characterising body condition parameters (resBCI) and glucose levels of nestlings associated with breeding birds foraging in extensively used meadows indicate good nutrition, but blood parameters suggest severe environmental stress, as is the case in the intensively used meadows fertilised with manure. The study aimed to determine the influence of grassland management on the potential food base of the red-backed shrike Lanius collurio and the condition of chicks in the population inhabiting semi-natural grasslands in the Narew floodplain. The grassland area was divided into three groups: extensively used meadows, intensively used meadows fertilised with mineral fertilisers, and intensively used meadows fertilised with liquid manure, and selected environmental factors that may influence food availability were determined. Using Barber traps, 1825 samples containing 53,739 arthropods were collected, and the diversity, abundance, and proportion of large arthropods in the samples were analysed depending on the grassland use type. In the bird population, the condition of the chicks was characterised by the BCI (Body Condition Index) and haematological parameters (glucose level, haemoglobin level, haematocrit, and H:L ratio). The diversity of arthropods was highest in extensively used meadows. Still, the mean abundance and proportion of arthropods over 1 cm in length differed significantly for Orthoptera, Hymenoptera, Arachne, and Carabidae between grassland use types, with the highest proportion of large arthropods and the highest abundance recorded in manure-fertilised meadows. The highest Body Condition Indexes and blood glucose levels of nestlings indicating good nestling nutrition were recorded in nests of birds associated with extensive land use. The H:L ratio as an indicator of the physiological condition of nestlings was high on manure-fertilised and extensively managed meadows, indicating stress factors associated with these environments. This suggests that consideration should be given to the effects of chemicals, such as pesticides or drug residues, that may come from slurry poured onto fields on the fitness of red-backed shrike chicks. [ABSTRACT FROM AUTHOR]

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The boreal owl (Aegolius funereus) has a circumpolar distribution, typically inhabit extensive conifer forest of higher age classes in the northern hemisphere. Breeding biology, reproductive strategies, and behavioural ecology of these nocturnal birds are well studied in Europe and North America. However, the knowledge of the subspecies of boreal owl (A. f. beickianus) in the coniferous forests at high mountainous altitude of the Qinghai-Tibet Plateau is still limited. We spent 10 years studying the breeding biology of A. f. beickianus in Lian Hua Shan Nature Reserve (Gansu Province), where we could first confirm the occurrence of this small forest dwelling owl in 1995. During breeding seasons (2003-2009, 2017-2019), we checked nest boxes and recorded the basic breeding data. Thereby a total of 51 broods were found with an average of 5.1 ± 1.7 broods per year. The mean egg mass and volume was 12.42 ± 1.36 g and 12.85 ± 0.79 mm³, respectively. Mean clutch size per brood was 2.61 ± 0.64. The mean number of fledglings was 1.25 ± 0.31 per nesting attempt and 2.07 ± 0.38 per successful brood. Nestling period lasted 35.75 ± 2.80 days in total, but was divided in two stages: in the first stage, which lasted 16.75 ± 1.48 days, the female stood in the breeding hole with its nestlings. In the second stage, which lasted 17 ± 4.34 days until the fledglings left their nest, the female stood outside the hole. The individual fledglings left the nesting site in intervals of 2.55 ± 1.92 days. [ABSTRACT FROM AUTHOR]

Recent studies have shown the importance of Myanmar for the conservation of three 'Critically Endangered' vulture populations. From November 2022 to March 2023, we carried out rapid surveys on vulture nests and nesting tree characteristics in Ke Hsi Township, Shan Highlands. We recorded 10 nests of White-rumped Vultures, Gyps bengalensis, on five nesting trees from four different localities. Six nests were active, and six nestlings were observed; four nests were inactive or abandoned. Most of the nests were recorded on Ficus spp. and the mean nest height was 13.6 m (SD ± 4.1) above ground. This represents the first confirmed record of the breeding success of Whiterumped Vultures from Shan Highlands and confirms the ongoing presence of the species in Shan States. The population of G. bengalensis in Shan Highlands is small, but the confirmed breeding is significant in the wider context for this species. [ABSTRACT FROM AUTHOR]

Background and Research Aims: Little information exists on the breeding behavior of the Andean Condor (Vultur gryphus). Its global population, estimated at 6700 adult individuals, is declining throughout its distribution range. With less than 150 condors, the Endangered condor population in Ecuador is of conservation concern. This study aimed to analyze the breeding behavior of wild-born Andean Condors in Ecuador. Methods: Between 2009 and 2021, we monitored 22 egg-laying attempts in eight Andean Condor nests, evaluated the parental care of three breeding pairs of condors and recorded the species' interactions with other raptors and mammals during the nestling-rearing season, and examined the breeding success of an Andean Condor pair during a decade of monitoring. Results: Our breeding records indicated that Andean Condor lay eggs throughout the year, and 16 nestlings spent between six and 10 months in the nest before making their first flights. We found differences in the length of time that the parents remain with the nestling, and described agonistic encounters between condors and other raptors and a Spectacled Bear (Tremarctos ornatus) in the condor nesting areas. The breeding success of the monitored condor pair was 0.88 nestlings per clutch, and the female laid an egg on average every 15 months. Conclusion: Considering the small size of the Andean Condor population in Ecuador, studies on the breeding behavior of wild-born condors are a high research priority to assess population trends and prevent extinction. Specifically, we recommend further research on parental care, breeding success, nestling survivorship, and nesting phenology. Implications for Conservation: Beyond the importance of the protected area system, strategic planning of key areas for the maintenance of condor populations in the northern Andes must encompass the evaluation of new potential protected areas that offer direct benefits to these birds. These should include nesting sites in human-dominated landscapes such as rural Andean areas. [ABSTRACT FROM AUTHOR]

White‐rumped vultures (Gyps bengalensis) are critically endangered species, and protecting their habitats, particularly the nesting trees, may have a positive impact on their reproductive success. For a better understanding of vultures' habitat needs, the characteristics of nesting trees should be accounted. In this paper, we compare the characteristics of the trees that have vultures' nests and that do not by randomly select a control tree within a 10 m radius of the nesting tree. We extensively searched and monitored the white‐rumped vultures' nests, nesting trees, and nesting tree species in Nepal between 2002 and 2022, and measured the characteristics of sampled trees such as their height, girth, canopy spread, branching orders, and whorls. We recorded 1161 nests of white‐rumped vulture in total on 194 trees belonging to 19 species over the past two decades. White‐rumped vultures preferred the kapok trees (Bombax ceiba) for nest construction than other tree species (χ2 = 115.38, df = 1, p <.001) as 66.49% of nests were built on them. In the logistic regression model, the number of whorls on a tree, canopy spread, and the height of the first branch determined whether a nest was present or absent on a tree. These results help to prioritize the tree attributes in a habitat conservation plan for vultures. [ABSTRACT FROM AUTHOR]

Intraspecific phenotypic variability is key to respond to environmental changes and anomalies. However, documenting the emergence of behavioral diversification in natural populations has remained elusive due to the difficulty of observing such a phenomenon at the right time and place. Here, we investigated how the emergence of a new trophic strategy in a population subjected to high fluctuations in the availability of its main trophic resource (migrating songbirds) affected the breeding performance, population structure, and population fitness of a specialized color polymorphic predator, the Eleonora's falcon from the Canary Islands. Using long-term data (2007–2022), we found that the exploitation of an alternative prey (a local petrel species) was associated with the growth of a previously residual falcon colony. Pairs in this colony laid earlier and raised more fledglings than in the other established colonies. The specialization on petrels increased over time, independently of annual fluctuations in prey availability. Importantly, however, the positive effect of petrel consumption on productivity was stronger in years with lower food availability. This trophic diversification was further associated with the genetically determined color morph, with dark individuals preying more frequently on petrels than pale ones, which might promote the long-term maintenance of genotypic and phenotypic diversity. We empirically demonstrate how the emergence of an alternative trophic strategy can buffer populations against harsh environmental fluctuations by stabilizing their productivity. [ABSTRACT FROM AUTHOR]

Greece holds the third larger breeding population of Dalmatian Pelican in the world. We present data about the establishment and growth, breeding performance and conservation status for all six colonies of the species in Greece for 40 years. Main features of wetlands and colonies are described. We discuss the local, regional and global natural and anthropogenic factors that may have affected colony growth. After 1982 colony surveys were carried out with various methods, adapted to the particularities of each wetland and availability of resources, and targeted estimating number of nests and number of near-fledged young via direct counting either during on-site visits or from vantage points, and recently, counts on photos taken by drones flown one or more times during breeding. Number of nests in Lake Mikri Prespa rose from ca. 100 to 1200-1500 and levelled-off. DPs from Prespa started breeding successfully in Kerkini in 2004 after placement of artificial nesting rafts. The Karla Reservoir was colonised in 2011, just two years after it started filling with water. The DP colony on Lake Chimaditis, an important stop over and feeding site, probably initiated around 2016 and continues growing. The two colonies at the western coastline have limited exchanges with those in the eastern part of the country. Amvrakikos increased and levelled off recently as conservation and management measures restricted disturbance, whilst emigrants re-established the old colony at Messolonghi in 2011 which continues to grow. The overall breeding population in Greece grew from ca 100 to over 2000 br pairs showing an annual growth rate of 7.9%. Younger colonies show high annual growth rates clearly attributed to immigration, while older colonies have growth rates less than 10%. Interacting natural and anthropogenic factors are assumed to have contributed to pelican increase in Greece the last 40 years: better legal protection status, increasingly effective protection, patrolling and conservation measures; public awareness campaigns; provision of artificial nesting structures; increased winter survival due to higher temperatures owed to climate change; less disturbance and persecution due to decline of fisheries; increasing abundance and availability of fish due to eutrophication and climate change; increasing numbers of sympatric great cormorants rendering pelican fishing more efficient; appearance of new wetlands and change of wetlands due to human intervention works.

We investigated the survival of cubs in a wild Indian leopard (Panthera pardus fusca) population in the Jhalana Reserve Forest (JRF), India. The research focuses on analyzing the survival of leopard cubs during their first two years of life. Survival functions were estimated using the Kaplan–Meier method based on data collected with trail cameras over four years from 2018 to 2021. We found that the mean survival probability of cubs during the first year of life was 0.739, indicating that this period is particularly challenging for their survival. In the second year, the survival probability increased to 0.831, reflecting an improvement in survival as the cubs grew older. The combined survival rate over the two-year period, calculated as the product of the first- and second-year survival rates, was 0.618. These findings highlight the critical periods in the early life stages of leopard cubs, which are essential for developing effective conservation strategies in fragmented habitats to enhance their survival.

Optimal clutch size theory predicts a trade-off between egg number and fledgling body mass, potentially affecting their survival rate. Yet, only a few studies have directly linked clutch or brood size to energy (food), nestling growth rate, and timing of breeding. We studied the relationship among all these variables in the Eurasian eagle owl. Of 150 eggs laid in 48 nests, 119 hatched and 117 nestlings fledged, indicating low nestling mortality. The number of eggs, hatchlings and fledglings (possibly indicating territory quality) decreased with ordinal date. The total amount of food brought to the nest increased with brood size, but the average amount per nestling decreased. Nestling growth rate (and thus probably fledgling body mass) was negatively correlated with brood size. A trade-off between brood size and fledgling survival may lessen the benefit of occupying food-rich territories. However, we suggest that fledglings from large broods, despite their relatively low body mass, may have higher survival rates owing to their relatively early fledging. This may be due to: (1) higher prey abundance in late spring compared with late summer and (2) a longer period before entering the cold season. Variation in brood size may therefore represent a set of strategies linked to prey abundance. [ABSTRACT FROM AUTHOR]

Darwin's finch species in the Galápagos Islands are famously distinguished by their morphology but less attention has been given to behavioral differences between species. In this study, we compared behavior between four Darwin's finch species on Floreana Island: small ground finch (Geospiza fuliginosa), medium ground finch (G. fortis), small tree finch (Camarhynchus parvulus), and medium tree finch (C. pauper). After capturing birds using mist-nets, we measured three behavioral traits: (1) boldness during human handling, (2) exploration in a novel environment, and (3) aggressiveness towards their mirror image. First, we found that ground finches were bolder and more exploratory than tree finches, consistent with their distinct ecological niches on Floreana Island and with the theoretical prediction that diet generalists should be less wary of novelty. Second, we tested the ecological validity of these behavioral variables at the individual level by relating them to territory defense behavior and breeding success. We found that males that were more exploratory in the novel environment also reacted more aggressively to a simulated territory intruder and showed lower offspring hatching success during the breeding season. Hence, our findings support previous work showing behavioral differences between Darwin's finch species and also suggest pathways by which behavioral differences among individuals might influence fitness. Significance statement: Closely-related species that overlap in their geographical range may differ in their morphology and/or behavior, allowing them to occupy different ecological niches. In this study, we explored behavioral differences between four Darwin's finch species on Floreana Island in the Galápagos Archipelago. We found clear interspecies differences in behavior, with the ground finches struggling more often during handling (boldness) and visiting more sectors in a novel environment (exploration) compared to the tree finches. After birds were released, we continued to observe a subset of male finches in the wild. An individual's exploration behavior significantly predicted both its aggressive response to a territory intruder (simulated using song playback) and offspring hatching success during the breeding season. This suggests that individual differences in exploration behavior can potentially be used as a proxy for territorial behavior in the wild and may also predict fitness outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: In this overview of the literature, we explore the complex endogenous and exogenous factors influencing the success of ovine artificial insemination (AI). From genetic dynamics and age-related fertility variations to the complexities of cervical anatomy and semen quality, we explore the nuances impacting ovine AI. Additionally, we examine the ongoing debate between natural and hormonal synchronization, semen handling, and the profound effects of environmental stressors like heat and nutritional stress. Our findings suggest that a holistic approach, considering both endogenous and exogenous factors, is crucial for optimizing AI outcomes in sheep breeding programs. This overview of the literature serves as a valuable guide for researchers, veterinarians, and sheep breeders, offering practical insights to enhance the efficiency and success of ovine AI programs and contribute to improved reproductive outcomes and genetic progress. Artificial insemination (AI) plays a vital role in animal breeding programs. AI is applied to enhance animal genetics and facilitate the widespread integration of desirable characteristics with a high potential for productivity. However, in sheep, this biotechnology is not commonly practicable due to multi-factorial challenges, resulting in inconsistent outcomes and unpredictable results. Thoughtful selection of semen donors and recipients based on genetic merit deeply impacts ovine AI outcomes. Additionally, endogenous factors such as breed, age, fertility traits, genetic disorders, and cervical anatomy in ewes contribute to ovine AI success. Extensive research has studied exogenous influences on sexual behavior, reproductive health, and hormonal regulation, all impacting ovine AI success. These exogenous factors include techniques like estrus induction, synchronization, semen handling methods (fresh/chilled/frozen), and insemination methods (cervical/laparoscopic), as well as nutritional factors and climatic conditions. This overview of the literature highlights the endogenous and exogenous challenges facing successful ovine AI and proposes strategies and best practices for improvement. This paper will serve as a guide for understanding and optimizing the success of ovine AI. [ABSTRACT FROM AUTHOR]

Food supply stands out as one of the most critical drivers of population demographics by limiting reproductive rates. In this study, we assessed fluctuations in diet composition and monitored various reproductive parameters over a nine-year period in a Golden Eagle population in an Eastern European peatland. The identification of 2439 prey specimens from 84 species revealed that the studied eagles primarily preyed upon birds (constituting 78.3% of prey numbers and 67.2% of prey biomass) and less on mammals (21.6% and 32.8%, respectively). Grouse emerged as the most important prey group (31% and 27%), followed by waterfowl (17%) and hares (8% and 14%). The most significant prey species, both in terms of numbers and weight, were the Black Grouse, Mountain Hare, Common Crane, and Capercaillie. The share of the Black Grouse decreased, while those of the White-fronted Goose, Roe Deer, and hares increased. The food niche, as measured by the Levins' index, was broad (6.6), and it expanded during the study. On average, 58.3% of Golden Eagle pairs initiated breeding annually, with 69.1% successfully completing it, and 0.41 young per occupied territory were produced annually; there was pronounced interannual variation in reproductive performance. These fluctuations were associated with the shares of White-fronted Goose, Capercaillie, Mountain Hare and Roe Deer in the diet, suggesting that these species may be gaining increasing importance for the Golden Eagle, particularly following the decline of the Black Grouse. [ABSTRACT FROM AUTHOR]

In the present study, I summarized the data on Common Crane (Grus grus) nesting published in the Hungarian ornithological literature from the mid-19th century to the present day. Based on these data, it can be observed that the crane was never a frequent nesting species in Hungary. It probably nested regularly until the early 19th century, then occasionally until the 1910s, after which, apart from two occasional reports, no nesting data were available until 2015. From this year onwards, it started nesting again in the Transdanubian region. In the examined period, 55.6% of the nests (n=25) originated from the Transdanubian region, 37.0% from the Tiszántúl region, and 7.4% from the Duna-Tisza area. The observations recorded during the nesting period showed a strong correlation with the spatial distribution of confirmed nests. 82.6% of the observations recorded (n=23) were from the Transdanubian region, 13.0% from the Tiszántúl region, and 4.3% from the Duna-Tisza region. The distribution of nesting data between regions varies not only spatially but also temporally. The nesting data from the Duna-Tisza area and Tiszántúl region date back to the 19th century, with the exception of one report, while the most recent nesting data are from the Transdanubian region (Vas and Veszprém counties). [ABSTRACT FROM AUTHOR]

Intermittent breeding is an important tactic in long‐lived species that trade off survival and reproduction to maximize lifetime reproductive success. When breeding conditions are unfavourable, individuals are expected to skip reproduction to ensure their own survival.Breeding propensity (i.e. the probability for a mature female to breed in a given year) is an essential parameter in determining reproductive output and population dynamics, but is not often studied in birds because it is difficult to obtain unbiased estimates. Breeding conditions are especially variable at high latitudes, potentially resulting in a large effect on breeding propensity of Arctic‐breeding migratory birds, such as geese.With a novel approach, we used GPS‐tracking data to determine nest locations, breeding propensity and nesting success of barnacle geese, and studied how these varied with breeding latitude and timing of arrival on the breeding grounds relative to local onset of spring.Onset of spring at the breeding grounds was a better predictor of breeding propensity and nesting success than relative timing of arrival. At Arctic latitudes (>66° N), breeding propensity decreased from 0.89 (95% CI: 0.65–0.97) in early springs to 0.22 (95% CI: 0.06–0.55) in late springs, while at temperate latitudes, it varied between 0.75 (95% CI: 0.38–0.93) and 0.89 (95% CI: 0.41–0.99) regardless of spring phenology. Nesting success followed a similar pattern and was lower in later springs at Arctic latitudes, but not at temperate latitudes. In early springs, a larger proportion of geese started breeding despite arriving late relative to the onset of spring, possibly because the early spring enabled them to use local resources to fuel egg laying and incubation.While earlier springs due to climate warming are considered to have mostly negative repercussions on reproductive success through phenological mismatches, our results suggest that these effects may partly be offset by higher breeding propensity and nesting success. [ABSTRACT FROM AUTHOR]

IntroductionSeabirds and other insular birds are an important part of marine ecosystems and are increasingly threatened worldwide. Phenology, abundance, distribution, and breeding success are important baseline parameters needed to evaluate population trends and dynamics, identify biodiversity hotspots and potential breeding sites, and assess habitat selection. In the Red Sea basin, reliable and complete data on birds are lacking for islands in most of the Important Bird Areas (IBA). Such data are now especially important since development projects have started at several of these locations. Here, we assess the distribution, abundance, phenology, and population trends of 13 bird species that breed in the Duba Islands, Al Wajh Bank, and Al Lith Islands. Breeding success and habitat selection for six species were also assessed.MethodsBetween December 2020 and August 2023, more than 90 islands were visited multiple times with different frequencies. All nests were counted, and the area occupied by the different colonies was georeferenced. Breeding success was assessed by visiting selected colonies multiple times until the chicks were ready to fledge. Habitat selection was determined by analyzing the habitat found in the georeferenced colonies.ResultsMore than 25,000 nests were counted each year, mainly in the summer, on more than 75 islands. Of the 13 species studied, the most abundant and widespread species was the White-cheeked tern, and the second most widespread was the Osprey.DiscussionWe estimate that the Al Wajh Bank hosts the following percentages of global breeding populations: Crab plover: 5%, Sooty gull: 17%–35%, White-eyed gull: 15%, Bridled tern: 1%, White-cheeked tern: 4%, and Lesser crested tern: 2%, making the area a regional and global hotspot for these species. Some of the islands occupied by breeding birds are slated for development for tourism activities as part of the Kingdom’s tourism expansion plans. At the same time, there are several ambitious conservation programs underway in these areas. To be effective, such programs require reliable and comprehensive data of the kind presented here.

Abstract White‐rumped vultures (Gyps bengalensis) are critically endangered species, and protecting their habitats, particularly the nesting trees, may have a positive impact on their reproductive success. For a better understanding of vultures' habitat needs, the characteristics of nesting trees should be accounted. In this paper, we compare the characteristics of the trees that have vultures' nests and that do not by randomly select a control tree within a 10 m radius of the nesting tree. We extensively searched and monitored the white‐rumped vultures' nests, nesting trees, and nesting tree species in Nepal between 2002 and 2022, and measured the characteristics of sampled trees such as their height, girth, canopy spread, branching orders, and whorls. We recorded 1161 nests of white‐rumped vulture in total on 194 trees belonging to 19 species over the past two decades. White‐rumped vultures preferred the kapok trees (Bombax ceiba) for nest construction than other tree species (χ2 = 115.38, df = 1, p

AbstractThis research was carried out in north-eastern Poland, where Whooper Swan Cygnus cygnus is a sparse breeder. Whooper Swan is timid and exhibits a tendency to hide in emergent vegetation. A drone was used to improve the effectiveness of research into its breeding success and offspring productivity. The breeding density of Whooper Swan in the study area in 2022 was 10 pairs/100 km2. The number of breeding birds detected at the beginning of the breeding season did not differ according to the method used (drone vs ground). The breeding productivity of the sample of swans studied (N = 36) was 2.19 cygnets per breeding pair using the ground method, but 3.71 per pair with the drone, a significant difference (p-value of the Wilcoxon test = 0.0148). The traditional method showed that 50% of the pairs had bred successfully, whereas with the drone this figure was 79%. The birds either did not react to the drone’s presence or else moved slowly away. The drone study of Whooper Swan breeding productivity was considerably faster (9 min per site vs 1–2 h ground survey), more precise, and less invasive for the birds than a traditional ground survey.