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Simple Summary: Nest sites for cavity-breeding birds are limited in many habitats such as in agriculture. Nest boxes are artificial nest sites that are added to provide birds a place to breed in areas where natural nest sites are lacking. For example, nest boxes are used to increase barn owl numbers in agricultural areas to reduce rodent damage in farmlands. Although nest boxes are added in different locations such as on poles and trees and in sunlight/shade, it is still unknown which location is better. Here, we compared the occupation of nest boxes by barn owls on trees, nest boxes on poles in the shade, and on poles in the sun. We found that more nest boxes were occupied when they were located on trees, followed by nest boxes on poles in the shade and nest boxes on poles in the sun. The number of nestlings raised in the nest boxes varied seasonally, with more being fledged early in the season in nest boxes located on poles in the sun whereas more nestlings were fledged later in the season in nest boxes located on trees. The seasonal difference is most likely due to the lower internal temperatures in nest boxes located on trees than in nest boxes on poles in the sun. Depending on the climate, it is important to consider variation in temperatures when adding nest boxes. Nest boxes have been used for years to increase breeding bird numbers for conservation and also in biological pest control projects. Barn owls (Tyto alba) have been used as biological pest control agents for rodents for years, and since nest boxes are costly for growers there is a need to determine whether nest box placement can increase the occupation of nest boxes and breeding success. We studied whether barn owl breeding in agricultural areas varied in nest boxes located on trees, poles located in the shade, and poles in the sun. The occupation of nest boxes was highest in nest boxes located on trees, followed by poles in the shade, and finally poles in the sun. In comparison, the number of fledglings was highest for nest boxes on poles in the sun followed by poles in the shade in the first half of the breeding season, whereas more nestlings were fledged in nest boxes on trees in the second part of the breeding season, which is most likely due to the higher internal temperatures in the nest boxes located in the sun. Interestingly, all the nest boxes' internal temperatures were lower than the ambient temperatures but were much lower on trees than those on poles, most likely due to the trees providing better protection from the heat. It is therefore important to not only consider the placement of nest boxes, but how occupation and breeding success may vary seasonally. [ABSTRACT FROM AUTHOR]

Natural breeding sites for amphibians are decreasing in quantity and quality in temperate regions, resulting in local extinctions and increasing population fragmentation. Artificial water bodies (e.g., water tanks or cattle troughs) can represent suitable reproductive habitats for some amphibians, but demographic data are required to assess this assumption. We evaluated the role of artificial water bodies in the persistence of a species of population concern, the common midwife toad, Alytes obstetricans (Laurenti, 1768), at local and regional scales. We surveyed 275 water bodies to characterize the distribution of the species and detected 63 breeding populations of A. obstetricans where we estimated larval abundance. In addition, we monitored two populations for three consecutive breeding seasons using capture-mark-recapture methods based on photo-identification, assessing abundance, breeding success and the use of space of adult individuals captured on multiple occasions. Our results show that artificial sites are preferentially used as breeding sites in the region compared to natural aquatic habitats, providing key habitat for the species and hosting much larger numbers and densities of larvae than natural sites. At local scale, populations of A. obstetricans in artificial sites were abundant and characterized by high male breeding success. However, adults are spatially aggregated around breeding sites, with small home ranges, implying high vulnerability to population fragmentation. Our results suggest artificial breeding sites can sustain viable populations of A. obstetricans , provided measures promoting connectivity among breeding nuclei are considered. [ABSTRACT FROM AUTHOR]

The Short-eared Owl (Asioflammeus) inhabits open grasslands and belongs to the ground-breeding birds that have experienced the most severe declines during recent decades. Here, we studied nest and fledgling survival of the owl species in relation to (i) habitat composition, (ii) vegetation structure, (iii) weather conditions and (iv) vole abundance. The study was conducted on the East Frisian Island of Spiekeroog (southern North Sea, Lower Saxony, Germany), which harbours one of the last remaining permanent populations of the species in Central Europe. With a mean hatching success of 5.6 young per nest (N = 34) and an average probability of nest survival of 0.9 (N = 28), values ascertained in this study exceeded those reported in previous research. We attribute this to the special environmental conditions on the island, i.e. (i) the absence of mammalian mesopredators such as the Red Fox (Vulpesvulpes), (ii) nearly no disturbance through agricultural measures and (iii) low level of human disturbance due to legal regulations of the National Park. By contrast, the survival of fledglings was lower than survival of nests and varied considerably between the investigated years. Weather conditions were the key driver of fledgling survival. Maximum wind speed and sunshine duration had a negative effect on the probability that chicks successfully fledged. Both lead to reduced hunting success, and the former is also associated with increased costs for thermoregulation. Consequently, increasing frequency of extreme weather events caused by climate change could negatively impact the breeding success of vole-dependent raptors, such as the Short-eared Owl. [ABSTRACT FROM AUTHOR]

Since 1992, Dutch volunteers have monitored the breeding attempts of Barn Swallows on a systematic basis. For two regions – Noord-Veluwe and Twente – a dataset of 27 years (1992–2018) was available. This paper examines the timing of breeding and the number of fledglings per successful breeding attempt. As spring and summer weather in Western Europe became on average warmer during this period, we analysed whether Barn Swallows adapted to this shift. The laying date of first broods advanced on average 2.3 days per ten years. The average advancement of laying date of second broods was 2.9 days per decade. The average number of fledglings per successful breeding attempt was constant over time, but showed large inter-year-variation. First broods consistently produced 0.6 fledglings more than second broods. These results are in line with results from similar studies in Western Europe. Contrary to our expectations, neither large scale nor local weather parameters were found to explain the advancement of laying and the number of fledged young. It is essential to study key species like Barn Swallows during all stages of their life cycle over a long time span and large spatial scale to be able to unravel potential effects of climate change. Our study demonstrates that volunteers can contribute essential demographic data. Ideally, these demographic parameters would be monitored with individually marked (colour-ringed) birds. Frequent quality checks and feedback to volunteers are key to maximize the quality of the data collected through long-term volunteer surveys. [ABSTRACT FROM AUTHOR]

The White-throated Cacholote Pseudoseisura gutturalis is a little studied, socially monogamous furnariid, endemic to arid Argentina. Here we provide novel information to characterize the breeding biology of the northern subspecies ochroleuca in the Monte Desert, Argentina, and discuss the similarities and differences with other Pseudoseisura species. Nests were bulky enclosed structures constructed with thorny sticks and twigs of native plant species (n = 15) and 47% of them had objects used as external decorations. Nests had an entrance tube oriented preferentially towards the northeast, probably to avoid the prevailing south-southeast winds at the study site, and were placed at a mean height of 2.1 m above the ground (n = 13). Most of the active nests (93%) were built in columnar cacti Trichocereus atacamensis that were healthier and with fewer branches than nearby available conspecifics. Mean clutch size was 3.2 white eggs (n = 9) and the incubation period was c. 18–20 days. Brood size ranged from one to three hatchlings (n = 12) and nestlings remained in the nest for 24–26 days until fledgling. Nests with complete clutches were found between 29 October and 1 February and nestlings were found between 1 November and 5 February. Nestlings were attended by both parents and were fed with arthropods (n = 63) and vertebrates (n = 7). Nest visitation rate per nestling was similar among nests with three and two nestlings and lower than for a nest with one nestling. The breeding success was high during the incubation (73%) and nestling rearing (82%) stages. Our data show that Pseudoseisura species are similar in some aspects of their breeding biology (e.g. nest dimensions, nest decorations, mating system, clutch size), whereas other aspects, such as nest-site selection, nestling period and nest attendance rate, are more variable among species. [ABSTRACT FROM AUTHOR]

The effect of anthropogenic disturbance on nesting Chimney Swift (Chaetura pelagica) is poorly described. We review five case studies of anthropogenic disturbance around Chimney Swift nest sites caused by building construction, demolition, and maintenance activities in St. Adolphe, Manitoba. Chimney Swift behaviour and nest site activity did not appear to be overtly influenced by building demolition and construction conducted on adjacent buildings or lots within 13-30 m of nest chimneys. In contrast, Chimney Swift behaviour and breeding success appeared to be negatively affected by loud interior renovations and rooftop work conducted in or on the same building as the nest chimneys. The presence of humans on the roof of the nest building prevented Chimney Swifts from entering the nest site and reduced the overall rate of feeding young. Based on these observations, we provide conservation best practices for building construction and maintenance projects conducted within or on the same building as nest chimneys to help ensure protection of Chimney Swifts and their nesting habitat during the breeding season. [ABSTRACT FROM AUTHOR]

The breeding biology of White-throated Kingfisher Halcyon smyrnensis was studied in plains and hilly areas from September 2008 to August 2011. Four villages under Savar upazilla were selected for plains, and Chittagong University Campus, Chattagram for the hilly area. The breeding season started in February in hills and April on plain. Mean (SD) time required to build a new nest was 11.3 (3.9) days in plains and 15.3 (0.57) days in hills. Clutch size was 3-4 in hills and 3-7 in plains. Mean egg parameters (length, width, and weight) and mean egg volume and surface area were similar in both areas. The mean incubation period on plains was 16.4 (1.2) days, in hills 14.1 (0.7) days. On plains fledging success was 52􀐹, compared to 57􀐹 in hills. The􀅌 by local inhabitants was a major reason for fledgling loss in plains, hence increased public awareness may reduce nestling mortality and increase breeding success. [ABSTRACT FROM AUTHOR]

As birds adapt to life in urban areas, separate urban populations are formed which are, in regards to many biological and ecological characteristics, distinct from birds of the same species that inhabit natural environments. The woodpigeon is one of the most common representatives of synurbic bird species that has successfully managed to spread to cities in most of Europe over the past century. This article explores the history of formation of synurbic woodpigeon groups in Belarus and looks at the differences in the breeding biology of forest and urban birds based on research in 2000–2021. During this period, we collected information about 109 woodpigeon nests in forest areas and 368 nests in urban areas. In the course of our research, we found out that the synurbic woodpigeon continues spreading to northern and eastern parts of Belarus. By now, urban birds live in around 70% of the entire territory of the country. Our analysis of the woodpigeon breeding biology shows that there are differences between forest and urban birds that stem from the fact that the latter live in urban areas. Despite the absence of clear differences in the phenology of the arrival of the woodpigeon in cities and natural landscapes, the nesting period of urban birds starts earlier and lasts much longer. In addition, the share of birds that breed more than once per season is larger than in forest birds. The peculiarities of nesting sites observed in urban birds as opposed to wild birds result from the peculiarities of urban green spaces and the effect of predation. We discovered that the share of nest failures peaks in spring (April–May). The breeding success of the woodpigeon in urban areas amounts to 52% of all nesting cases. [ABSTRACT FROM AUTHOR]

The lack of suitable nesting sites is one key driver behind the farmland bird crisis in Europe. Winter cereals become impenetrable for ground‐breeding birds like the Eurasian Skylark (Alauda arvensis), curtailing breeding time. Stable Skylark populations depend on multiple breeding attempts per year; thus, the widespread cultivation of winter cereals has strongly contributed to their tremendous decline. Crop diversification is thought to be a potential measure to counteract this development. Therefore, we explored how individual Skylarks respond to the decreasing suitability of winter cereals as nesting habitats in heterogeneous but otherwise conventionally managed farmland. Our study focused on: (i) the degree to which Skylarks prematurely cease nesting activity, switch nesting habitats, or breed on linear structures like tramlines. Additionally, we analyzed: (ii) if nest success decreases throughout the breeding season and (iii) how often Skylarks make a successful breeding attempt per year. We radio‐tagged 28 adults in a German population during April 2018 and 2019, tracked half of them for more than 3 months, and measured their breeding success. Additionally, we monitored nests of untagged pairs, resulting in 96 nests found. None, except one tagged individual, stopped breeding activity before July 1st. Home ranges were mainly stable, but Skylarks switched nesting habitats away from winter cereals to crops like sugar beet or set‐aside. High‐risk nesting sites like corn and linear structures played a minor role in breeding. Overall, Mayfield logistic regressions revealed no seasonal decrease in nest success, and tagged Skylarks had sufficient time to make 1.5–1.8 breeding attempts, of which 0.8 were successful. We suggest that heterogeneous farmland in our study area, which enabled diversely composed home ranges, prevented a curtailment of the breeding season. Thus, our study reinforces the need for crop diversification which gives Skylarks a chance to survive in modern farmland. [ABSTRACT FROM AUTHOR]

Top-predators serve as sentinels of ecosystem health due to their sensitivity to environmental contamination. However, our understanding on how contaminants affect individual fitness is still scarce, especially for long-lived species. Here, we measured blood concentrations of 4 metals (Cd, Cu, Pb, and Zn) and one metalloid (As) in black kite (Milvus migrans) adults from Doñana National Park (SW Spain) following a major mine spill. Besides temporal variation (1998-2001) in metal and As concentrations, we tested how metal and As profiles changed across individuals in relation to their sex, age or breeding status, and examined whether metal and As concentrations affected individuals' fitness (breeding success and mortality). We found that, overall, blood concentrations of Pb, Cd and As increased throughout the study period in black kites, mirroring the progressive increase previously reported for their main prey. Both sex (Cu and Zn) and breeding status (Zn and Pb) affected element concentrations. Non-breeding (floater) females had higher levels of Zn than their breeding counterparts. The same pattern of higher contamination in floaters was observed for Pb, which might be related to differences in diet and foraging activity between breeders and floaters. The percentage of the individuals with Pb concentrations that exceeded toxicity thresholds (> 200 μg/L) was relatively high (15.4 %). Moreover, Pb concentrations were negatively correlated to males' breeding success. We found no clear evidence to support metal and As effects on survival or life expectancy after accounting for environmental and individual sources of variation. Our results highlight the importance of long-term studies of marked individuals in wild populations; detailed knowledge of ecological processes relevant to these populations, combined with measures of contaminant exposure at individual level, provides opportunities to enhance our understanding of its fitness effects and potential demographic consequences., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Abstract In birds, obtaining information related to nest occupancy, offspring status or breeding success is essential for population monitoring, particularly for species of conservation concern. Traditionally, nest monitoring demands a lot of time and effort in order to gather accurate information and avoiding nest disturbance. Instead, Unmanned Aerial Vehicles (UAVs, hereafter drones) present an alternative to traditional methods, but few studies have been done measuring their influence on birds’ behavior and reproductive success. We addressed the utility of drones equipped with an on‐board camera in examining nesting status of the endangered Chaco Eagle Buteogallus coronatus in semiarid environments of central Argentina, as well as the degree of disturbance of drone flights to individuals. We performed 76 drone flights at 41 Chaco Eagle nests registering flight duration, tree height, nest relative height and pilot proximity to nest. Of those, 38 flights were done over occupied nests where we recorded adult behavior. Before drone took off, most adult eagles remained in the nests or in the surroundings (

In migratory systems, variation in individual phenology can arise through differences in individual migratory behaviors, and this may be particularly apparent in partial migrant systems, where migrant and resident individuals are present within the same population. Links between breeding phenology and migratory behavior or success are generally investigated at the individual level. However, for breeding phenology in particular, the migratory behaviors of each member of the pair may need to be considered simultaneously, as breeding phenology will likely be constrained by timing of the pair member that arrives last, and carryover effects on breeding success may vary depending on whether pair members share the same migratory behavior or not. We used tracking of marked individuals and monitoring of breeding success from a partially migrant population of Eurasian oystercatchers (Haematopus ostralegus) breeding in Iceland to test whether (a) breeding phenology varied with pair migratory behavior; (b) within‐pair consistency in timing of laying differed among pair migratory behaviors; and (c) reproductive performance varied with pair migratory behavior, timing of laying, and year. We found that annual variation in timing of laying differed among pair migratory behaviors, with resident pairs being more consistent than migrant and mixed pairs, and migrant/mixed pairs breeding earlier than residents in most years but later in one (unusually cold) year. Pairs that laid early were more likely to replace their clutch after nest loss, had higher productivity and higher fledging success, independent of pair migratory behavior. Our study suggests that the links between individual migratory behavior and reproductive success can vary over time and, to a much lesser extent, with mate migratory behavior and can be mediated by differences in laying dates. Understanding these cascading effects of pair phenology on breeding success is likely to be key to predicting the impact of changing environmental conditions on migratory species. [ABSTRACT FROM AUTHOR]

Weather conditions can profoundly affect avian reproduction. It is known that weather conditions prior to and after the onset of reproduction can affect the breeding success of birds. However, little is known about how seasonal weather variability can affect birds' breeding performance, particularly for species with a slow pace of life. Long-term studies are key to understanding how weather variability can affect a population's dynamics, especially when extreme weather events are expected to increase with climate change. Using a 32-year population study of the Blue-footed booby (Sula nebouxii) in Mexico, we show that seasonal variation in weather conditions, predominantly during the incubation stage, affects offspring survival and body condition at independence. During most of the incubation period, warm sea surface temperatures were correlated with low hatching success, while rainfall in the middle of the incubation stage was correlated with high fledging success. In addition, chicks from nests that experienced warm sea surface temperatures from the pre-laying stage to near-fledging had lower body condition at 70 days of age. Finally, we show that variable annual SST conditions before and during the incubation stage can impair breeding performance. Our results provide insight into how seasonal and interannual weather variation during key reproductive stages can affect hatching success, fledging success, and fledgling body condition in a long-lived neotropical seabird. [ABSTRACT FROM AUTHOR]

The breeding of most high-altitude birds remains poorly known. We studied the breeding ecology of Kessler's thrush (Turdus kessleri) and documented reproductive information throughout the nestling periods in the western Sichuan plateau. The data included natural nest sites, nest components, nest size, egg-laying dates, egg morphology, egg size, clutch size, egg incubation, nestling brooding and feeding, nestling morphology and growth, and reproductive outcome. The study found that T. kessleri used the old nest to breed. As the nestling grew, the female's nestling brooding time decreased, and the feeding frequency of parent birds increased at first and then decreased. The frequency of clearing feces was positively correlated with the feeding frequency. The difference in the feeding frequency of both parents may be attributed to their division of labor, with a distinct difference between their investments. The parent birds' cost of reproduction per nestling varies from one breeding period to the next. Predation by natural enemies is the main factor leading to reproductive failure in T. kessleri. This suite of life-history and behavioral strategies enables fledgling T. kessleri to cope with the harsh environments of mountains at higher altitudes. [ABSTRACT FROM AUTHOR]

Identifying the factors influencing seabird breeding output is critical for their conservation because breeding performance in turn influences population dynamics. This is particularly important in sensitive environments, where ecological disturbances can lead to changes in population trends of extremely specialized species in a relatively short time. Here, we have reported on the breeding output of the Adélie penguin Pygoscelis adeliae in three colonies of the Mid Victoria Land, Ross Sea (Antarctica), in 2017/2018–2018/2019 to provide scientific information for the Ross Sea Marine Protected Area research and management plan. Breeding chronology, breeding success and chick growth did not differ between study colonies and were in line with data reported for other penguin colonies across Antarctica. Penguin breeding success was higher in central than in peripheral nests and decreased with an increasing number of neighboring nesting skuas; conversely, at-nest weather conditions experienced by chicks did not seem to play a role. Our findings suggest that the quality of the nesting environment seems more important than the general condition of the colony in determining breeding output. Therefore, along with marine habitat characteristics for the planning of management and conservation of seabirds, the importance of the terrestrial environment must be also duly considered. [ABSTRACT FROM AUTHOR]

Globally, high‐amplitude variation in weather (e.g. precipitation) is increasing in frequency and magnitude. This appears to be so for the southern Murray‐Darling Basin, Australia, where droughts of unprecedented (in the instrumental record, extending back to the mid‐1800s) depth and duration (1997–first half of 2010; second half of 2012–) are being punctuated by extreme wet periods, albeit of shorter duration ('Big Wet', second half of 2010–first half of 2012). We have previously reported on the responses of floodplain‐forest birds to the cessation of the longest recorded drought ('Big Dry', 1997–first half of 2010), but we found little evidence of a rebound, at least shortly after the Big Wet. However, we reasoned that there may have been insufficient time for the birds to have responded in that short time, so we repeated the survey program 5 years after the end of the Big Wet (2017). Bird occurrences, reproductive activity and success were substantially greater compared with late in the Big Dry (2009) than they had been soon after the Big Wet (2013). However, bird occurrences still fell well below measurements in the early‐Big Dry (1998), so that the avifauna appears to be in decline, most probably because the length of drought periods far exceeds that of wet periods giving the birds too little time to recover fully. [ABSTRACT FROM AUTHOR]

Understanding important factors for breeding Eared Grebes (Podiceps nigricollis) is essential for its conservation. We aimed to study the impact of some factors on nests and breeding success in this species in fishponds (S Poland). Number of Eared Grebe nests were counted on particular carp ponds. Pond size, vegetation cover, number of nests in colonies of associated gull or tern species, and age of stocked common carp (Cyprinus carpio) were determined for all ponds with nests. We also investigated the relationship between nest size, material used to construct them and clutch size. Number of Eared Grebe nests positively correlated with number of breeding pairs of associated colonial species (terns or gulls). Selection of the breeding site by the Eared Grebe can be explained by appropriate nest protection by large colonies of associated species (Whiskered Tern Chlidonias hybrida and Black-headed Gull Chroicocephalus ridibundus). Nest size was not related to clutch size. A negative relationship between breeding success and number of nests of Eared Grebe was found. Food is a not limiting factor for the Eared Grebe on fishponds with extensive production, and presumably other factors such as weather conditions may explain the low breeding success of this species. [ABSTRACT FROM AUTHOR]

Predation is one of the most important factors influencing breeding success. Many bird species suffer from high losses because of predators. I studied breeding success and replacement broods in the Red-breasted Flycatcher Ficedula parva. The Red-breasted Flycatcher is a small bird breeding in natural holes in dense deciduous and mixed forests of Europe. Data were collected during twelve breeding seasons in a primeval forest, in the Bialowieża National Park, Northeast Poland, the best preserved and protected area of the Białowieża Forest with a rich community of birds and mammals including predators. Almost half of the broods of the Red-breasted Flycatcher were lost and most of them because of predation. In cases where the brood was lost in the period of egg laying or incubation, females tended to lay a replacement clutch. First and replacement nest-sites differed insignificantly in characteristics, but new clutches were always laid in a new site. Out of 68 broods, in which a loss was found, replacement broods were recorded in 47.1% cases. Replacement clutches were much smaller and pairs raised significantly fewer fledglings. The proportions of successful and lost broods were similar in the first and replacement attempts (56.1%, and 46.7%, respectively). Red-breasted Flycatchers choose shallow nest-sites that allow the females to observe their surroundings. This allows the female to escape from the nest when a predator approaches, increasing the possibility of a repeat clutch and the attainment of breeding success in the same season. [ABSTRACT FROM AUTHOR]

Dam construction for the provision of hydropower and a stable water supply poses a major threat to freshwater biodiversity. Water fluctuation due to dam management has adverse effects on local people and biodiversity in downstream areas, including sandbar-nesting birds. The aim of this research was to determine the effect of water levels controlled by upstream dams on the breeding success of two sandbar-nesting birds, the little ringed plover, Charadrius dubius, and little pratincole, Glareola lacteal, along the Mekong River in Bueng Kan Province, Thailand. During January–May 2018, we found 160 active nests of only two species, the little ringed plover (n = 26 nests, 288 exposure days) and the little pratincole (n = 134 nests, 890 exposure days). Their nest success rates were 19.49 ± 7.52% and 5.54 ± 1.61%, respectively. Predation was a major cause of nest failure for both species (n = 82), followed by flooding (n = 44). We found a significantly increased probability of nest flooding when the water level was higher than when the nest was initiated for those located closer to the water, particularly during March and April, when water levels fluctuated. Our results indicate that dams threaten sandbar-nesting species. [ABSTRACT FROM AUTHOR]

Abstract In migratory systems, variation in individual phenology can arise through differences in individual migratory behaviors, and this may be particularly apparent in partial migrant systems, where migrant and resident individuals are present within the same population. Links between breeding phenology and migratory behavior or success are generally investigated at the individual level. However, for breeding phenology in particular, the migratory behaviors of each member of the pair may need to be considered simultaneously, as breeding phenology will likely be constrained by timing of the pair member that arrives last, and carryover effects on breeding success may vary depending on whether pair members share the same migratory behavior or not. We used tracking of marked individuals and monitoring of breeding success from a partially migrant population of Eurasian oystercatchers (Haematopus ostralegus) breeding in Iceland to test whether (a) breeding phenology varied with pair migratory behavior; (b) within‐pair consistency in timing of laying differed among pair migratory behaviors; and (c) reproductive performance varied with pair migratory behavior, timing of laying, and year. We found that annual variation in timing of laying differed among pair migratory behaviors, with resident pairs being more consistent than migrant and mixed pairs, and migrant/mixed pairs breeding earlier than residents in most years but later in one (unusually cold) year. Pairs that laid early were more likely to replace their clutch after nest loss, had higher productivity and higher fledging success, independent of pair migratory behavior. Our study suggests that the links between individual migratory behavior and reproductive success can vary over time and, to a much lesser extent, with mate migratory behavior and can be mediated by differences in laying dates. Understanding these cascading effects of pair phenology on breeding success is likely to be key to predicting the impact of changing environmental conditions on migratory species.

Although density-dependent processes and their impacts on population dynamics are key issues in ecology and conservation biology, empirical evidence of density-dependence remains scarce for species or populations with low densities, scattered distributions, and especially for managed populations where densities may vary as a result of extrinsic factors (such as harvesting or releases). Here, we explore the presence of density-dependent processes in a reinforced population of North African Houbara bustard (Chlamydotis undulata undulata). We investigated the relationship between reproductive success and local density, and the possible variation of this relationship according to habitat suitability using three independent datasets. Based on eight years of nests monitoring (more than 7000 nests), we modeled the Daily Nest Survival Rate (DNSR) as a proxy of reproductive success. Our results indicate that DNSR was negatively impacted by local densities and that this relationship was approximately constant in space and time: (1) although DNSR strongly decreased over the breeding season, the negative relationship between DNSR and density remained constant over the breeding season; (2) this density-dependent relationship did not vary with the quality of the habitat associated with the nest location. Previous studies have shown that the demographic parameters and population dynamics of the reinforced North African Houbara bustard are strongly influenced by extrinsic environmental and management parameters. Our study further indicates the existence of density-dependent regulation in a low-density, managed population.

Abstract Background Energy landscapes provide an approach to the mechanistic basis of spatial ecology and decision-making in animals. This is based on the quantification of the variation in the energy costs of movements through a given environment, as well as how these costs vary in time and for different animal populations. Organisms as diverse as fish, mammals, and birds will move in areas of the energy landscape that result in minimised costs and maximised energy gain. Recently, energy landscapes have been used to link energy gain and variable energy costs of foraging to breeding success, revealing their potential use for understanding demographic changes. Methods Using GPS-temperature-depth and tri-axial accelerometer loggers, stable isotope and molecular analyses of the diet, and leucocyte counts, we studied the response of gentoo (Pygoscelis papua) and chinstrap (Pygoscelis antarcticus) penguins to different energy landscapes and resources. We compared species and gentoo penguin populations with contrasting population trends. Results Between populations, gentoo penguins from Livingston Island (Antarctica), a site with positive population trends, foraged in energy landscape sectors that implied lower foraging costs per energy gained compared with those around New Island (Falkland/Malvinas Islands; sub-Antarctic), a breeding site with fluctuating energy costs of foraging, breeding success and populations. Between species, chinstrap penguins foraged in sectors of the energy landscape with lower foraging costs per bottom time, a proxy for energy gain. They also showed lower physiological stress, as revealed by leucocyte counts, and higher breeding success than gentoo penguins. In terms of diet, we found a flexible foraging ecology in gentoo penguins but a narrow foraging niche for chinstraps. Conclusions The lower foraging costs incurred by the gentoo penguins from Livingston, may favour a higher breeding success that would explain the species’ positive population trend in the Antarctic Peninsula. The lower foraging costs in chinstrap penguins may also explain their higher breeding success, compared to gentoos from Antarctica but not their negative population trend. Altogether, our results suggest a link between energy landscapes and breeding success mediated by the physiological condition.

Abstract Changes in the physical environment along the Antarctic Peninsula have been among the most rapid anywhere on the planet. In concert with environmental change, the potential for direct human disturbance resulting from tourism, scientific programs, and commercial fisheries continues to rise in the region. While seabirds, such as the gentoo penguin Pygoscelis papua, are commonly used to assess the impact of these disturbances on natural systems, research efforts are often hampered by limited spatial coverage and lack of temporal resolution. Using a large‐scale remote time‐lapse camera network and a modeling framework adapted from capture‐recapture studies, we assess drivers of intra‐ and inter‐annual dynamics in gentoo penguin breeding success across nearly the entire species’ range in the Atlantic sector of the Southern Ocean. We quantify the precise timing of egg/chick mortality within each season and examine the role of precipitation events, tourism visitation, and fishing activity for Antarctic krill Euphausia superba (a principal prey resource in the Antarctic) in these processes. We find that nest failure rates are higher in the egg than the chick stage and that neither krill fishing nor tourism visitation had a strong effect on gentoo penguin breeding success. While precipitation events had, on average, little effect on nest mortality, results suggest that extreme weather events can precipitate sharp increases in nest failure. This study highlights the importance of continuous ecosystem monitoring, facilitated here by remote time‐lapse cameras, in understanding ecological responses to environmental stressors, particularly with regard to the timing of events such as extreme weather.

Seabirds are compelled to nest on land, away from their feeding areas, which they can only reach by leaving eggs or chicks in the nest, often for long periods of time. For this reason, almost all of them have evolved social monogamy as a reproductive system, cooperation between partners for incubation and chick rearing, and long-lasting pair bonds. Additionally, nesting conditions are essential for successful reproduction, and the nest can be considered a resource if it provides more guarantees in this aspect. As a result, the nest may be a source of contention and intraspecific competition, especially among males. In this work, we analyze long-term data of the Scopoli’s shearwater (Calonectris diomedea) population to address the fitness consequences of nest change regarding survival and reproductive success. We used capture–recapture multistate models and the AICc model selection approach to test three hypotheses: breeding failure triggers nest change; nest change affects breeding success probability; nest change affects survival. Each year, about 5% of the breeders move to a new nest. For males, it was mainly a way to improve their breeding conditions and was observed in their early years as a breeder. Conversely, for females, it was a way to improve their reproductive performance by trying with a new mate after a failure. Males that changed nests improved their breeding success probability. Instead, in females, there was no causal relation between nest change and breeding success, the latter having been more influenced by the intrinsic quality of the female as a breeder. We did not even find a link between nest change and survival. Instead, we demonstrated that reproductive failure could affect the apparent survival of females, probably because it induces breeding dispersal.

Rapid progress is being made in understanding how dispersal strategies influence the spread of species whose ranges are expanding. However, potentially vital dispersal behaviours have so far been neglected. Social species have been demonstrated to use their own breeding performance (personal information) and the breeding performance of their conspecifics (public information) to inform both their emigration and settlement decisions. Here, to provide insight into how these behaviours may impact range expansion dynamics, we extend a recently‐developed individual‐based model that incorporates the use of personal and public information in emigration decisions and a prospecting phase informing settlement decisions. We find that compared to non‐informed emigration, informed emigration results in slower range expansions, except when individuals prospect a high number of patches or when their perceptual range is high. Spread rate and also the extent of the front strongly depend upon the willingness of individuals to settle in an empty patch. Given the likely prevalence of prospecting and informed dispersal across a wide range of taxa, these results indicate an urgent need for further empirical and modelling studies to improve our understanding and predictive capability of how species exhibiting this informed dispersal strategy will respond to environmental changes. [ABSTRACT FROM AUTHOR]

Unmasking the ecological processes responsible for the dynamics of a population is a necessary step toward understanding its threats and viability. We examined a fitness proxy (reproductive success) of an endangered raptor in relation to its ecological niche and spatial distribution to provide insights into the dynamics and potential threats to the population. We first studied how biotic and abiotic conditions drive both the spatial distribution of Bonelli's eagle (Aquila fasciata) and its long‐term reproductive success in a large area of northwestern Spain. We focused on the relationship between these two characteristics of the population. Our results showed that biotic factors (occurrence of competitors such as the golden eagle or prey availability) were more associated with the spatial distribution of the species than with its reproductive success. In contrast, abiotic factors describing climate were linked to reproductive success. Most interestingly, we found a mismatch between spatial suitability and reproductive success because reproduction was compromised in the areas that were more suitable for the occurrence of the species. The results suggest that productivity (less than one chick per year), measured as long‐term reproductive success, may compromise the population viability and suggest the presence of an underlying mechanism in the population. Our results highlight the benefits of simultaneously considering both large‐scale spatial distribution patterns and measures of fitness, which often require larger investments of time, for endangered species conservation programs. [ABSTRACT FROM AUTHOR]

The productivity of raptors is affected by different factors such as habitat, food supply, disturbance, weather conditions, and competition. Of the studied breeding parameters, success rate and breeding success significantly decreased over the years, while fledgling success and breeding density showed no trend. This study shed light on the main factors influencing the breeding success of a medium-sized raptor expanding in Europe from Asia. Modeling the factors determining the breeding success, we found that grassland availability, mean temperature during fledgling period and rainfall during nestling period influenced Long-legged buzzard reproduction (ΔAIC = 0.00, wi = 0.42, p = 0.03). The second significant model was described by weather factors excluding presence of grasslands (ΔAIC = 1.03, wi = 0.25, p = 0.05). Examining the explanatory factors, only presence of grassland in the territories demonstrated some effect on buzzard productivity. The assumption that other factors such as human disturbance, Souslik density, habitat diversity, and presence of competitors shaped buzzard's productivity did not find support in this study. This study supports the prediction of the future of Long-legged buzzard as it explored the effects of habitat and weather on its reproduction in the southern part of its distribution range. The conditions of a large-scale habitat alteration on one hand and, on the other hand, global climate change, manifested in increased rainfall during spring in Europe, draw an uncertain future for this species. Therefore, restoration of grasslands and proper habitat management, ensuring sufficient and diverse prey, is crucial for conservation of the Long-legged buzzard. [ABSTRACT FROM AUTHOR]

Population viability analyses (PVA) are now routinely used during the consenting process for offshore wind energy developments to assess potential impacts to vulnerable species, such as seabirds. These models are typically based on mean vital rates, such as survival and fecundity, with some level of environmental stochasticity (i.e., temporal variation). However, many species of seabird are experiencing population decline due to temporal (i.e., directional) trends in their vital rates. We assess the prevalence of temporal trends in rates of fecundity for a sentinel species of seabird, the black‐legged kittiwake Rissa tridactyla, and examine how accounting for these relationships affects the predictive accuracy of PVA, as well as the projected population response to an extrinsic threat. We found that temporal trends in kittiwake rates of fecundity are widespread, and that including these trends in PVA assessments dramatically influences the projected rate of population decline. We advocate that model validation become a prerequisite step in seabird PVA assessments to identify potential biases influencing the projected population response. We also argue that environmental factors driving current population dynamics need to be incorporated in PVA impact assessments as potential "worst‐case" scenarios. These findings have immediate application for improving and reducing uncertainty in impact assessments conducted as part of the consenting process for offshore wind energy developments. [ABSTRACT FROM AUTHOR]

The aim of this study was to test the influence of nest site characteristics and food supplementation from rubbish dumps on reproductive parameters of white storks breeding in semi-arid habitats. A total of 148 nests were monitored in two colonies of white storks (control colony vs. colony that benefited from high food supply in rubbish dumps) in eastern Algeria over a six-year period (2011–2016) to measure nest characteristics and reproductive parameters (clutch size, number of hatchings, number of fledglings, breeding success). Results showed that pairs breeding at proximity from rubbish dumps had larger clutch sizes (5.1 ± 0.6 vs. 4.6 ± 0.6), hatched more chicks (4.7 ± 0.7 vs. 4.3 ± 0.7) and raised more fledglings (3.0 ± 0.9 vs. 2.6 ± 1.0) than pairs breeding far from rubbish dumps. Results also showed that clutch size was positively related to nest surface area, and that pairs nesting on electricity poles had a lower breeding success than those nesting in trees (48.9 ± 20.4% vs. 64.6 ± 17.6%). Our findings suggest that breeding outputs are strongly related to selective behavior in nest placement and food availability surrounding the nesting site. [ABSTRACT FROM AUTHOR]

Burrowing seabirds are important in ecological and conservation terms. Many populations are in flux due to both negative and positive anthropogenic impacts, but their ecology makes measuring changes difficult. Reliably recording key metrics, the proportion of burrows with breeding pairs and the success of breeding attempts requires burrow‐level information on occupancy. We investigated the use of camera traps positioned at burrow entrances for determining the number of breeding pairs in a sample to inform population estimates, and for recording breeding success. The performance of two cameras makes we tested differed markedly, with Spypoint Force 10 trail cameras prone to malfunction while Reconyx HC600 Hyperfire cameras performed well. Nevertheless, both makes yielded season‐long activity patterns for individual burrows, eliminating uncertainty around successful fledging attempts. Dimensionality reduction of activity metrics derived from camera time series suggests breeding and non‐breeding burrows may be identifiable using linear discriminant analyses but sample sizes from our trial were low and group means were only significantly different during certain breeding stages (permutational multivariate analysis of variance: early chick‐rearing f = 3.64, P = 0.06; late chick‐rearing f = 8.28, P = 0.009). Compared with traditional techniques for determining burrow occupancy (e.g. manual burrow inspection and playback of conspecific calls at burrow entrances), camera traps can reduce uncertainty in estimated breeding success and potentially breeding status of burrows. Significant up‐front investment is required in terms of equipment and human resources but for long‐term studies, camera traps may deliver advantages, particularly when unanticipated novel observations and the potential for calibrating traditional methods with cameras are factored in. [ABSTRACT FROM AUTHOR]

The choice of suitable nest materials is a key to nest-building process in birds. During the breeding season (March-August) in 2018 and 2019, we discovered that crested mynas (Acridotheres cristatellus) added snake slough (2–18.3 cm in length) to their nests. The addition of snake slough continued throughout the breeding period, with a proportion of 38.9% being during the nest-building period. The use of snake slough in 2018 (38.5%) was significantly less than in 2019 (71.4%). No significant differences were found in clutch size, egg mass, and egg size between nests with snake slough (the slough group) and nests without snake slough (the non-slough group). There were also no significant differences in the number of nestlings hatched for each nest, nestling growing and breeding success between the snake slough and the non-snake slough group. This is the first study to report that crested mynas add snake slough to their nests throughout their breeding period, but snake slough had little impact on most of the breeding parameters of crested mynas. We speculate that snake slough in crested myna nests may serve to reduce nest predation, improve the immunity of nestlings or serve as a post-mating sexual signal eliciting differential reproductive investment in mates; however, these speculations require further investigation.

Abstract Population viability analyses (PVA) are now routinely used during the consenting process for offshore wind energy developments to assess potential impacts to vulnerable species, such as seabirds. These models are typically based on mean vital rates, such as survival and fecundity, with some level of environmental stochasticity (i.e., temporal variation). However, many species of seabird are experiencing population decline due to temporal (i.e., directional) trends in their vital rates. We assess the prevalence of temporal trends in rates of fecundity for a sentinel species of seabird, the black‐legged kittiwake Rissa tridactyla, and examine how accounting for these relationships affects the predictive accuracy of PVA, as well as the projected population response to an extrinsic threat. We found that temporal trends in kittiwake rates of fecundity are widespread, and that including these trends in PVA assessments dramatically influences the projected rate of population decline. We advocate that model validation become a prerequisite step in seabird PVA assessments to identify potential biases influencing the projected population response. We also argue that environmental factors driving current population dynamics need to be incorporated in PVA impact assessments as potential “worst‐case” scenarios. These findings have immediate application for improving and reducing uncertainty in impact assessments conducted as part of the consenting process for offshore wind energy developments.

The objective of this study was to evaluate the effect of food supply in garbage dumps on the reproductive fitness of Cattle Egret Bubulcus ibis and offspring losses. A total of 236 nests were monitored during two distinct periods of 2 years for each: 146 nests during a period without food supply in dumps (1998-1999) and 90 with food supply in dumps (2007-2008). The study was carried out in the colony of El-Kseur in the Lower Soummam Valley (northeast Algeria). For the entire study period, the mean of clutch size, average number of hatched chicks, productivity, and breeding success varied significantly between years (Kruskal-Wallis test: p < .05). Also, the average calculated losses for eggs, chicks, and total offspring vary significantly (Chi2 test: p > .0001). The clutch size and the number of hatched chicks per nest were highest during the period with food supply in garbage dump (respectively: 3.46 ± 0.86; 2.85 ± 1.11), compared to the period when cattle egrets feed in natural or agricultural habitats (3.04 ± 0.87; 2.54 ± 1.03). However, productivity and breeding success were highest during the period without food supply (respectively: 2.11 ± 1.16 fledging's/nest; 0.70 ± 0.35) than in the period with food supply (1.14 ± 0.91; 0.35 ± 0.30). While egg losses were substantially similar between the two study periods, chick's mortality (59.9%) and total offspring losses (36.7%) were higher during the period with food supply. The generalized linear mixed model (GLMM) analysis indicated a large negative effect of food supply in dumps on the productivity, on the chick's losses; and a positive effect on the total offspring losses (p < .001). Also, feed in dump garbage revealed a significant negative effect on the breeding success linear mixed model (LMM, p = .01). However, no significant effects (GLMM, p > .05) of food supply in dumps were noted on average clutch size, the mean number of hatched chicks per nest, and egg losses. [ABSTRACT FROM AUTHOR]

Nesting and breeding success of red-vented bulbul (Pycnonotus cafer) were studied in orchards, parks and agriculture fields in Renala Khurd, district Okara, Punjab, Pakistan. A total of 69 nests were located in the study area; breeding activity was observed in 51 active nests. The successful nests for breeding activity were recorded in parks (46%) followed by orchards (28%) and agricultural fields (27%). Highest percentage of successful nests was found on forks (48%) while nests on middle, terminal and other positions of plants were recorded as 17%, 10% and 25%, respectively. The preferred height for nest construction was recorded 1-2m (58%) followed by 2-3m (17%), 0-1m (16%), 3-4m (7%) and 4-5m (1%). The bulbul prefers to make nests on northern white cedar (Thuja occidentalis; 32%) followed by guava (Psidium guajava; 19%), mango (Mangifera indica; 9%), white mulberry (Moris alba; 9%), sweat orange (Citrus X sinensis; 9%), babul (Vachellia nilotica; 7%), banyan (Ficus bengalensis; 4%), weeping fig (Ficus benjamina; 3%) and date palm (Phoenix dactylifera; 3%). The highest number of nests were recorded with clutch size 3 (87%) followed by 2 (11%) and 4 (2%). A total of 154 eggs were observed in 51 nests, from which 10% eggs were infertile, 19% were predated and other losses counted 4%. A total of 104 eggs under observation were hatched, from which 28% chicks were predated and 6% fell out from the nest. The fledgling success was the highest in parks (65%) compared to orchards (25%) and agricultural fields (10%). It is concluded that bulbul preferred to construct nests on northern white cedar in parks. Moreover, breeding success was higher in parks compared to orchards and agricultural fields. [ABSTRACT FROM AUTHOR]

Studies regarding the cinereous vulture (Aegypius monachus), classified globally as near threatened, have recently accelerated in Turkey. Comprehensive studies particularly about the northwestern Anatolian population, have been conducted. Also, the genetic studies carried out, have revealed that the cinereous vulture population in Turkey is panmictic and that it has recently suffered a bottleneck. The main aim of this study conducted across the Köroğlu Mountains in Bolu was to determine the population size and the breeding success of the species. A total of 37 field surveys in 2018 and 2019 have revealed Turkey's largest breeding cinereous vulture colony and have detected 60 breeding pairs. However, breeding success remained low. Considering this and other pertinent population studies, at least 200 pairs are estimated to breed in northwestern Anatolia. Conservation of the species is crucial in terms of the health and sustainability of the ecosystem; therefore, data related to nests must be incorporated into local forest management plans to sustain the Cinereous vulture population and breeding here. [ABSTRACT FROM AUTHOR]

The White Tern (Gygis alba) is a common seabird that nests on islands in tropical and subtropical oceans. In the southeastern Hawaiian Islands, White Terns breed only in urban and suburban areas of Honolulu. The Honolulu population has grown from a single pair in 1961 to 2,300 birds in 2016. We measured breeding success of White Terns in Honolulu and examined aspects of their breeding biology and the environment that may affect breeding. We documented 3,855 breeding events in Honolulu from 2016 to 2019. Breeding success was 68.3% and varied less than 3% among years. Breeding occurred in all months, with lowest activity in the summer and a peak in the winter and spring, but the pattern varied among years. White Terns bred in 64 tree species. Breeding success varied among tree species and was related to characteristics of the trees and their attractiveness to non-native predators. The height of breeding events was 9.26 ± 0.05 m and success was related to height, with higher success in events 5–10 m above ground. The diameter of branches on which breeding occurred was 10.2 ± 0.1 cm and success was related to branch diameter, with lower success on branches >20 cm. The high breeding success of White Terns in Honolulu is related to: the small size and isolation of the O'ahu population, which may result in reduced intra-specific competition for food; protection from predators provided by the urban environment; and trimming of trees by arborists, which unintentionally improves the value of trees as breeding sites for terns. [ABSTRACT FROM AUTHOR]

We monitored the Northern Goshawk Accipiter gentilis at six sites in Japan to determine trends in the number of breeding pairs. In addition, to identify changes in the reproductive performance of goshawks at a wide geographic scale, breeding data was collected from via web form from observers nationwide and were analyzed regionally. From 2001 to 2021, the number of breeding pairs of goshawks at the six monitoring sites decreased significantly by 2.8%/year. From 2016 to 2021, the proportion of previouslyknown nests that failed to breed had increased in the Kanto and Chubu regions. Also, a significant decreasing trend in the number of fledglings was observed at 47 nests under continuous survey. On September 21, 2017, the Northern Goshawk was removed from the list of "Nationally Endangered Species of Wild Fauna and Flora" under the Law for the Conservation Endangered Species of Wild Fauna and Flora. The present results do not point to a direct effect attributable to removal from the list. Our data, however, indicates reduced breeding performance and a decline in the number of active pairs, and we recommend continued monitoring of those parameters. [ABSTRACT FROM AUTHOR]

Philopatry and monogamy are conventionally viewed as strategies for improving fitness. Many philopatric and monogamous species have, however, been shown to perform breeding dispersal—an exchange of territory (and often also partner) between two breeding seasons. The adaptiveness of breeding dispersal remains controversial, as data remain scarce and sporadic. For the Northern Goshawk, a typically highly philopatric and monogamous forest raptor, pairs breeding in barren forest landscapes produce fewer fledglings than pairs breeding in more productive landscapes. Using data on Finnish breeding female Goshawks (Accipiter gentilis) during 1999–2016, we tested the hypotheses that: (1) breeding dispersal is more likely at barren territories, (2) dispersing females move to less barren territories, and (3) breeding dispersal improves the survival of young. About 29% of the female Goshawks in our study performed breeding dispersal, which contrasts to philopatry and suggest that site and partner fidelities show large variation within the species' breeding range. We found no evidence that territorial landscape barrenness (proxy on habitat quality) affects the probability of breeding dispersal. However, females that dispersed upgraded to less barren territories. Nevertheless, there were no subsequent effects of breeding dispersal on reproductive performance, suggesting no obvious difference in the capability of rearing young at either site. Although dispersal events were directed to less barren habitats, we suggest that female dispersal is not driven by the pursue for more prospersous habitats, rather that those females are forced to move, for whatever reason. In addition to other observed reasons such as female–female competition for mates and loss of the original mate, intense logging of mature forests lowering local food availability and restricting nest site availability were likely a partial cause of increased breeding dispersal. [ABSTRACT FROM AUTHOR]

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So far, much effort has been invested in the conservation of vulnerable freshwater habitats, yet their number still displays a decreasing tendency worldwide. Although many species have accepted man-made wetlands, their frequent disturbance may have a negative impact on these species. In this study, we examined the effects of human disturbance on the Great Reed Warbler, Acrocephalus arundinaceus, nesting population in a semi-urban reed habitat (canal) in Sombor, north-western Serbia. We found that Great Reed Warblers avoided nesting in canal sections where humans altered the reed and bank vegetation by cutting and building piers and other objects. The nesting population moved to other, less disturbed canal sections. Despite the disturbance, the breeding parameters, such as brood parasitism, nest predation, nest desertion and nesting success, did not show significant variations. We conclude that human disturbance does not change breeding performance but may cause adult birds to leave the habitat. We suggest that any human disturbance should be limited and carefully undertaken by following governmental rules. [ABSTRACT FROM AUTHOR]

This paper presents modern methods for assessing the nest survival, which are implemented in the free software MARK. Using the example of the data of long-term monitoring of the breeding success of two passerine bird species, the capabilities of the method in assessing the intra- and interannual variability of the daily nest survival rate as well as the dependence of the latter on weather conditions are demonstrated. The analysis is based on a sample of 523 booted warbler (Iduna caligata) nests and 553 whinchat (Saxicola rubetra) nests monitored on abandoned fields of Vologda oblast in 2005–2018. The daily nest survival rates failed to differ between the two species and showed significant interannual variations. Intraseasonal variations in the daily survival rates were weaker than interannual ones. The daily nest survival rate depended nonlinearly on nest age, this effect showing different directions in different years. In some years, the mean daily air temperature rendered a significant impact on the nest daily survival rate. [ABSTRACT FROM AUTHOR]

The choice of suitable nest materials is a key to nest-building process in birds. During the breeding season (March-August) in 2018 and 2019, we discovered that crested mynas (Acridotheres cristatellus) added snake slough (2–18.3 cm in length) to their nests. The addition of snake slough continued throughout the breeding period, with a proportion of 38.9% being during the nest-building period. The use of snake slough in 2018 (38.5%) was significantly less than in 2019 (71.4%). No significant differences were found in clutch size, egg mass, and egg size between nests with snake slough (the slough group) and nests without snake slough (the non-slough group). There were also no significant differences in the number of nestlings hatched for each nest, nestling growing and breeding success between the snake slough and the non-snake slough group. This is the first study to report that crested mynas add snake slough to their nests throughout their breeding period, but snake slough had little impact on most of the breeding parameters of crested mynas. We speculate that snake slough in crested myna nests may serve to reduce nest predation, improve the immunity of nestlings or serve as a post-mating sexual signal eliciting differential reproductive investment in mates; however, these speculations require further investigation. [ABSTRACT FROM AUTHOR]

Ground-nesting Great Cormorants were monitored in three neighbouring colonies at Lake IJsselmeer, The Netherlands. Using aerial photographs taken during peak breeding time, nest density and nearest neighbour distance were determined for four sequential years. In addition, species and number of predators were determined. In total, five mammalian and nine avian predatory species were associated with the Cormorant breeding colonies. Spatial distribution of nests mostly showed dispersed and random patterns rather than a contagious pattern. The latter distribution, with less distance between nests than expected both from a random and equal distribution pattern, was found in the colony of De Ven in 2013 during the last year of its existence. The predator Red Fox Vulpes vulpes arrived at the colony in 2010. In all three colonies, nest density was highest and nearest neighbour distance shortest in colonies with the highest number of predators. At low to moderate predatory pressure, ground-nesting Cormorants left free space between nests that was used by adult birds during take-off and landing. During the last years of its existence the shrinking colony of De Ven showed an almost circular shape, with an extreme nest density and the lowest edge-to-surface area ratio. But with Foxes present, breeding at the fringe still caused greater losses due to direct predation. Breeding success fluctuated synchronously between colonies but was lower in colonies where the number of predators was higher. The arrival of Red Foxes in De Ven caused extreme losses of young and over the years resulted in a strong decline in number of breeders, eventually leading to complete abandoning of the site in 2014. Large gulls formed another important group of predators but did not cause the Cormorants to abandon the breeding site. In the Vooroever colony, bush and tree cover supplied shelter and allowed birds to breed in greater density without causing nearest neighbour density to decrease, as was the case when no cover was available. Greater nest density and reduced nearest neighbour distances are considered to be a pro-active response by individual birds to the presence of predators. When predator numbers increased, the within-colony open spaces that normally exist under circumstances of moderate density were filled up with nests, leaving little or no room for landing and departure. This leads to reduced edge effects and a circular shape of the colony, thereby potentially limiting predation risk. As a consequence of extreme high nest densities, breeding success was lower due to interference by other Cormorants. This study is the first to show that colony structure in waterbirds is affected by forces of attraction and repulsion between founding birds that are predator driven. [ABSTRACT FROM AUTHOR]

Great Cormorants Phalacrocorax carbo in the eastern Baltic are expanding in numbers. Eight colonies in Estonia, Finland and the Russian Federation were investigated in 2007. Brood size and condition of large nestlings were determined and indicate that food provisioning was not a limiting factor. Food items consisted of both pelagic and benthic prey, with marked differences among the colonies. Eelpout Zoarces viviparus and Roach Rutilus rutilus were the most important prey according to fish mass. For pelagic prey this was Sprat Sprattus sprattus. Additional data in later years support the conclusion that the species experienced a rapid expansion at the time of investigation. Two factors are likely to have contributed to improved conditions for Cormorants in this part of the eastern Baltic. First, the low abundance of predatory fish such as Cod Gadus morhua and Pikeperch Sander lucioperca as a result of overfishing by commercial fisheries as well as climate change has, most likely, caused small benthic and pelagic prey fish to thrive. Second, increased eutrophication has probably fuelled the fish production. Based on fish species taken and the number of Cormorants present, the conclusion seems justified that any interaction between Cormorants and fisheries is unlikely at the scale of the Finnish Gulf, although locally measurable effects of Cormorant consumption on commercial yield may exist. As a visible, relatively new apex predator to the system, the Great Cormorant may well be an indicator of the ecological condition of the system. Monitoring of Cormorants (numbers, distribution, food, breeding success) may therefore provide useful data which can be used to assess the recovery of the benthic and pelagic parts of the food web. [ABSTRACT FROM AUTHOR]

The recovery of the Baltic White-tailed Eagle Haliaeetus albicilla population since the 1980s is a conservation success story. However, the re-establishment of this predator in coastal and lake areas appears to affect Great Cormorants Phalacrocorax carbo during the breeding season. We collated published and unpublished records of White-tailed Eagle occurrence and interactions with Cormorant colonies as well as records of Cormorant anti-predator responses and effects on Cormorant breeding performance. We found evidence for immediate direct effects (mainly kleptoparasitism, predation of eggs and offspring) and indirect effects (facilitating nest predation by mainly gulls and corvids). Repeated disturbance from hunting White-tailed Eagles was also inferred to trigger changes in selection of nest sites, to cause complete abandonment of colonies and lead to regional redistributions of breeders. However, there are also observations of 'unproblematic' coexistence with White-tailed Eagles breeding inside Cormorant colonies. There is some evidence to suggest that nesting opportunities for Cormorants may become further restricted as White-tailed Eagle numbers continue to increase, and we argue that this – in some regions – will impose limitations on the distribution and size of breeding populations of Cormorants. [ABSTRACT FROM AUTHOR]