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Photographic monitoring currently provides the most accurate means for identifying nest predators and eventually their role in bird population declines worldwide. However, previous studies have found that commercially available trail cameras represent an artificial structure that tend to negatively bias predation rates, likely through predator neophobia. Based on an experiment in Arctic tundra, involving 50 artificial nests and 30 cameras in each of 2 breeding seasons, we demonstrated that trail cameras attracted corvids (in particular ravens [Corvus corax]), which caused an extreme and positively biased predation rate that was consistent over a range of experimental and environmental conditions. We call for new technologies that allow for photographic monitoring of bird nests with minimal visual footprints, in the form of smaller cameras and more efficient internal batteries to minimize novel and conspicuous external features detectable by predators. However, even such improved devices need to be assessed with respect to potential effects on nest predation in each case. [ABSTRACT FROM AUTHOR]

In many primate species, nest raiding is a form of opportunistic foraging behavior designed to acquire protein-rich eggs and nestlings. In urban environments, this is a significant cause of nest failure in birds. Here, we describe nest raiding and egg predation in bonnet macaques (Macaca radiata) inhabiting a suburban area of Salem, Tamil Nadu, India. During nest raiding, large-billed crows (Corvus macrorhynchos) and house crows (Corvus splendens), actively defended their nest from the macaques. When several macaque foragers jointly raided the nest, they were successful in obtaining and consuming the eggs. In contrast, when a solitary macaque attempted to raid the nest, it was unsuccessful. Bird size appeared to play an important role in nest defense. Small birds, such as the scaly breasted munia (Lonchura punctulata) and the purple sunbird (Cinnyris asiaticus) were not able to protect their nests from lone bonnet macaques. These observations indicate that in urban landscapes, bonnet macaques are egg predators of many bird species. When macaques coordinate their actions and forage in small subgroups, they were more successful in preying on the eggs of larger-bodied bird species. [ABSTRACT FROM AUTHOR]

The European pond turtle (Emys orbicularis) is a wide-ranging, long-living freshwater species with low reproductive success, mainly due to high predation pressure. We studied how habitat variables and predator communities in near-natural marshes affect the survival of turtle eggs and hatchlings. We followed the survival of artificial turtle nests placed in marshes along Lake Balaton (Hungary) in May and June as well as hatchlings (dummies) exposed in September. We found that the fewest nests remained intact in the least disturbed, most extensive area with the largest turtle population without predator control. Hatchlings, compared to nests had a significantly higher probability of survival. The density of carnivore dens indicated the negative influence on the number of exposure days, while marsh vegetation coverage was unrelated. The role of carnivores, especially the red fox (Vulpes vulpes) in the predation of nests was more significant, while predation by corvids (Corvidae) and wild boar (Sus scrofa) increased for the hatchlings. Predation by mammals increased with the limited availability of dry terrestrial surfaces suitable for laying eggs and with distance to water. Our multifactorial analyses highlight the need for targeted conservation efforts to improve the reproductive success of turtles in these ecologically sensitive environments. [ABSTRACT FROM AUTHOR]

Interactions with competitors and predators can generate strong selection and favour the evolution of novel strategies for mitigating fitness costs. Adaptations to mitigate competition and predation risk often involve evolution of traits which directly reduce costs. Simultaneously, the evolution of behaviours that co‐opt the functional traits of non‐interacting, third‐party species have also been observed but remain poorly studied (e.g. anointing behaviour, tri‐trophic interactions). Here we investigate if the novel behavioural co‐option of conifer resin in a cavity‐nesting bird can ameliorate interactions with nest predators and nest site competitors. Red‐breasted nuthatches (Sitta canadensis) collect resin from live trees and apply it around the entrances of their nest cavities in dead trees. Using paired nest boxes, we mimicked the nuthatch behaviour by apply resin around the hole of one and not the paired box in two field experiments to test a priori hypotheses about the evolution and adaptive value of this behaviour. The first experiment baited the paired boxes with food to attract mammalian predators (e.g. red squirrels Tamiasciurus hudsonicus). The second experiment left boxes available for breeding by cavity‐nesting birds that compete with nuthatches for nest sites (e.g. house wrens Troglodytes aedon). We also used ancestral trait reconstruction to test whether resin use is a non‐adaptive derivation of mud‐plastering behaviour observed in numerous congeners. Experimental nest boxes with resin applied to the entrance were less likely to have bait removed and less likely to have nests built or initiated than paired nest boxes without resin. Ancestral trait reconstruction suggested that resin use was more likely (>77%) to have evolved in ancestors that did not exhibit mud‐plastering behaviour. Our results do not support a major role of phylogenetic inertia and provide experimental evidence that application of conifer resin to nest cavities ameliorates interference competition from other cavity‐nesting species and reduces nest predation risk. Overall, our results showcase the ecological function of behavioural co‐option and its important consequences for fitness in nature. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Introduction: The "win-stay, lose-switch" (WSLS) strategy used by birds involves decisions to maintain or alter the characteristics of the subsequent nest according to the outcome of the previous one. In salt marshes, nest failure occurs due to flooding, predation, or tipping, creating a trade-off for nest placement: it should be low enough to avoid predators from above and tipping by the wind, and high enough to avoid flooding. In salt marshes of Southern Brazil, predation from above is carried out by rails that also prey on nests from below, promoting nondirectional pressure capable of neutralizing bird responses. We aim to test the WSLS strategy and to assess its adaptive significance for Formicivora acutirostris , the only thamnophilid endemic to salt marshes. Our general premise is that the adoption of the WSLS strategy would vary in response to the fate of the previous nest, considering also the environment type. Methods: We evaluated the fate, environment type, height, altitude, and thickness of nests of F. acutirostris in southern Brazil, between 2006 and 2023. We assessed the effects of the nest attributes, tested the adoption of the WSLS strategy, and explored its adaptive significance using generalized linear mixed models. We also examined the influence of factors such as nest environment, nesting timing, and pair age on nest fate and parental behavior. Results: We studied 98 renesting cases. Flooded nests were at a lower height than predated, tipped, and successful nests, and tipped nests were thicker than flooded and successful nests. Nest heights differed among environment types. The species adopted the WSLS strategy by increasing nest height after flooding, but we do not support its adaptive significance. No additional factors influenced the behavior of the species. Discussion: Although the adoption of the WSLS strategy by F. acutirostris was confirmed regarding the increase in nest height after flooding, it did not result in a significant increase in reproductive success, suggesting that other pressures, such as predation and tipping, are limiting the adaptive potential of this strategy. We emphasize the threat of the high reproductive failure for the conservation of F. acutirostris and proposes reducing predation pressure as an important conservation strategy. [ABSTRACT FROM AUTHOR]

Climate change is driving regime shifts across ecosystems, exposing species to novel challenges of extreme weather, altered disturbances, food web disruptions, and habitat loss. For disturbance-dependent species like the endangered piping plover (Charadrius melodus), these shifts present both opportunities and risks. While most piping plover populations show net growth following storm-driven habitat creation, similar gains have not been documented in the Eastern Canadian breeding unit. In September 2022, post-tropical cyclone Fiona caused record coastal changes in this region, prompting our study of population and nesting responses within the central subunit of Prince Edward Island (PEI). Using satellite imagery and machine learning tools, we mapped storm-induced change in open sand habitat on PEI and compared nest outcomes across habitat conditions from 2020 to 2023. Open sand areas increased by 9–12 months post-storm, primarily through landward beach expansion. However, the following breeding season showed no change in abundance, minimal use of new habitats, and mixed nest success. Across study years, backshore zones, pure sand habitats, and sandspits/sandbars had lower apparent nest success, while washover zones, sparsely vegetated areas, and wider beaches had higher success. Following PTC Fiona, nest success on terminal spits declined sharply, dropping from 45–55% of nests hatched in pre-storm years to just 5%, partly due to increased flooding. This suggests reduced suitability, possibly from storm-induced changes to beach elevation or slope. Further analyses incorporating geomorphological and ecological data are needed to determine whether the availability of suitable habitat is limiting population growth. These findings highlight the importance of conserving and replicating critical habitat features to support piping plover recovery in vulnerable areas. [ABSTRACT FROM AUTHOR]

Egg retrieval in birds may help ensure the survival of eggs and improve reproductive success. However, with the risk of brood parasitism, for ground-nesting or cavity-nesting bird hosts, there is a significant reproductive cost and thus a reduction in fitness if the host wrongly retrieved the parasitic eggs. The south rock bunting (Emberiza yunnanensis) and yellow-throated bunting (E. elegans) are hosts for common cuckoos (Cuculus canorus), which coexist within the study area and breed sympatrically in ground nests. Previous studies have found that these two species exhibit strong egg recognition and egg rejection of non-mimetic eggs. In this study, red model eggs, budgerigar eggs, and the host's own eggs were used to assess the recognition and retrieval behavior of two bunting hosts, particularly in response to different types of eggs placed at the nest edge. The results showed that both bunting hosts retrieved ca. 80% of own eggs and did not retrieve any red model eggs. This indicated that both species could distinguish non-mimetic model eggs from their own eggs and make appropriate decisions, which is consistent with their responses when encountering foreign eggs in the nest. However, both species simultaneously retrieved some (8.3% for the yellow-throated bunting and 19% for south rock bunting) of the highly mimetic budgerigar eggs, indicating that the degree of mimicry of foreign eggs affects their egg recognition and egg retrieval behavior. Factors such as parasitism risk, nest predation pressure, age differences, and experience of parent birds may combine to influence egg retrieval behavior of the host. [ABSTRACT FROM AUTHOR]

When two or more individuals cooperate to provision a shared brood, each carer may be able to maximize their payoffs by coordinating provisioning in relation to what others are doing. This investment "game" is not simply a matter of how much to invest but also of the relative timing of investment. Recent studies propose that temporal coordination of care in the forms of alternation (i.e. turn-taking) and synchrony (i.e. provisioning together) function to mitigate conflict between carers and reduce brood predation risk, respectively. Such coordination is widespread in biparental and cooperatively breeding birds, yet the fitness consequences have rarely been empirically tested. Here, we use a long-term study of long-tailed tits Aegithalos caudatus , a facultative cooperatively breeding bird with active coordination of care, to assess the support for these hypothesized functions for coordination of provisioning visits. First, we found evidence that turn-taking mitigates conflict between carers because, in cooperative groups, provisioning rates and offspring recruitment increased with the level of active alternation exhibited by carers and with the associated increase in provisioning rate parity between carers. In contrast, offspring recruitment did not increase with alternation in biparental nests, although it was positively correlated with parity of provisioning between carers, which is predicted to result from conflict mitigation. Second, synchronous nest visits were associated with a reduced probability of nest predation and thus increased brood survival, especially when provisioning rates were high. We attribute this effect to synchrony reducing carer activity near the nest. We conclude that temporal coordination of provisioning visits in the forms of alternation and synchrony both confer fitness benefits on carers and despite being intrinsically linked, these different kinds of coordination appear to serve different functions. [ABSTRACT FROM AUTHOR]

The nesting ecology of two wetland-dependent bird species, the Little Tern (Sternula albifrons) and the Small Pratincole (Glareola lactea) were studied in two seasonally emerged riverine islands, locally named as charlands in Padma River of Bangladesh. A total of 269 and 299 nests of Little Tern and Small Pratincole were found in the breeding season of 2022. We monitored 70 nests of the two species from two charlands, and the nesting success was 74.28% and 78.57%, respectively. No correlation was found between nesting success of both species in relation to clutch size, nest height, nest depth and presence of vegetation near nest. We found strong positive correlation between nesting success and nest distance to river for Little Tern. Nesting success was higher if the Little Tern's nests were located far from the river channel. However, no such trends were observed for Small Pratincole in the study area. The main factor affecting Little Tern nesting success was nest predation by avian predator (n = 6) and tropical storms (n = 3). On the contrary, eight Small Pratincole nests were predated by avian predators and four nests were lost due to storm. However, in case of 12 deserted nests (with unhatched eggs) of both species, no apparent reasons were identified. The study suggests that these charlands, if protected from human interferences, can provide great breeding support for colonial ground nesting waterbirds. [ABSTRACT FROM AUTHOR]

A breeding colony of the Lesser Black-backed Gull Larus fuscus was discovered at the Khenifiss lagoon on the Atlantic coast of southern Morocco. In June 2022, 222 nests were counted and, in 2023, 62 nests were present. Nests were built on sandy-clay soil on a natural saline flat without any vegetation cover. The mean calculated egg volume (69.10 ± 6.69 cm3; n = 33) was similar to that reported for European populations of this species. Predation was the main cause of breeding failure. This remarkable discovery constitutes the first evidence of reproduction of Lesser Black-backed Gulls in mainland Africa, thereby extending the species' known breeding range southwards by ∼2 000 km. This finding holds considerable implications for understanding this species' adaptability to new environments and the population dynamics driving range expansion. [ABSTRACT FROM AUTHOR]

Arctic‐breeding birds exhibit around‐the‐clock activity, and these activity cycles are postulated to maximize reproductive success during the short breeding season characteristic of high‐latitude regions. Two closely related species of arctic‐breeding songbirds, Lapland longspurs (Calcarius lapponicus; ground‐nesting) and snow buntings (Plectrophenax nivalis; cavity‐nesting) exhibit extended activity cycles throughout the polar day (71° N) except for 4–5 h of daily quiescence. Ground‐nesting Lapland longspurs experience higher levels of nest predation than cavity‐nesting snow buntings, and this difference is reflected in elevated nest vigilance in male longspurs compared with snow buntings. In this study, we examined the effect of melatonin supplementation upon male parental care, corresponding measures of nestling growth, and ability to reduce activity (and increase sleep). A pharmacological dose of melatonin in captive snow buntings dampened the amplitude of activity rhythms over the polar day with no detectable phase‐shifting compared with control‐implanted birds. Melatonin treatment reduced nest visits and overall time spent on the nest by male snow buntings compared with controls. There was no significant increase in time spent by female snow buntings on the nest to compensate for this, and there was no significant effect on offspring growth rates. There were no effects of melatonin supplementation on longspur adults or offspring, suggesting behavioral insensitivity to exogenous melatonin treatment. These differences in sensitivity underscore the importance of nest defense in ground‐nesting longspurs compared with cavity‐nesting snow buntings, which participate minimally in nest defense. Research Highlights: Melatonin supplementation altered male parental care in a cavity‐nesting arctic‐breeding bird, the snow bunting (Plectrophenax nivalis).Melatonin supplementation dampened activity rhythms.Lapland longspurs (Calcarius lapponicus), a ground‐nesting congener, were unaffected by melatonin treatment. [ABSTRACT FROM AUTHOR]

Predator activity can structure communities temporally and influence the spatial distribution of prey. Yet, despite the influence this may have on prey species' activity or geographic persistence, our understanding of whether diel predator activity changes geographically remains limited. Here, we conduct a case study to test whether predator activity during the darkest phase of the diel cycle increases with the duration of daylight (i.e. photoperiod) at high latitudes during summer, aligning with the photoperiod constraint hypothesis. Using both observations and experiments at one seabird colony above and one below the northern polar (Arctic) circle, we compared predator activity between the brightest and darkest phases of the diel cycle. Avian predator counts were greater and nest predation events were more common during the brightest phase of the diel cycle below the Arctic Circle (i.e. where the sun goes below the horizon) but similar across phases during polar summer (i.e. above the Arctic Circle when the sun does not set). Our results highlight the potential influence of light on activity of predator communities and suggest a possible latitudinal limit to the advantage gained by dark-active strategies for avoidance of visually hunting predators. [ABSTRACT FROM AUTHOR]

Nest predation rates critically influence avian biodiversity and evolution. In the north temperate zone, increased nest failure along edges of forest fragments is hypothesized to play a major role in the disappearance of bird species from disturbed landscapes. However, we lack comprehensive syntheses from tropical latitudes, where biodiversity is highest and increasingly threatened by habitat fragmentation and disturbance. We assembled data from five decades of field studies across the global tropics (1,112 populations of 661 species) and used phylogenetic models to evaluate proposed predictors of nest success. We found significant effects of several traits, including adult body mass and nest architecture. Contrary to results from many temperate locations, anthropogenic habitat disruption did not consistently reduce nest success; in fact, raw nest success rates were lower in large tracts of primary forest than in disturbed or fragmented landscapes. Follow-up analyses within species, using a subset of 76 species for which we had estimates of nest survival in habitats with different levels of disruption, confirmed that neither disturbance nor fragmentation significantly influenced nest success. These results suggest that nest predation alone cannot explain observed declines in avian biodiversity in tropical forest fragments, raising new questions about the demographic processes that drive extinction in the tropics. [ABSTRACT FROM AUTHOR]

The article explores the role of ephemeral river islands in the Meta River in eastern Colombia as habitats for migratory songbirds from the northern and southern hemispheres during migration and the nonbreeding period. The islands emerge during the dry season, providing roosting and foraging sites for thousands of migratory birds. The study highlights the importance of understanding the habitat use and quality of nonbreeding areas for long-distance migrants and raises questions about the ecological associations, spatial-temporal dynamics, and conservation priorities of these ephemeral islands. [Extracted from the article]

We studied the breeding ecology of Whinchats Saxicola rubetra in four tiny (less than 10 breeding pairs) populations in nature reserves in the Dutch province of Drenthe. We focussed on reproductive rates (laying date, clutch size, hatchling number, breeding success), proportion of unpaired males and nestling diet. Breeding pairs appeared to cluster together, thereby leaving other seemingly suitable parts of the area unoccupied. Clutch size, nest and pair success were similar to or higher than those in other studies. Laying of first eggs peaked during 16–20 May and laying dates had not advanced since the 1950s, in contrast to many other songbirds. We found 34% of the males remained unpaired, limiting the population reproduction rate. Whinchats provided their nestlings primarily with beetles and caterpillars and feeding frequency appeared to depend on prey species. Higher feeding frequencies may lead to a higher risk of nest predation. Being single-brooded, Whinchat populations may be more affected by nest predation than populations of multi-brooded species. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Field Ornithology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In European countries, raccoon dogs (Nyctereutes procyonoides) are believed to impact ecosystems and potentially threaten native species. In this study, the stomachs of 525 raccoon dogs culled in Danish wetlands were analysed and compared to 53 stomachs of adult raccoon dogs killed by vehicles, from the countryside. The stomach content was analysed using traditional macroscopic technics supplemented by eDNA analysis. The diet of raccoon dogs in wetlands did not differ notably from that of raccoon dogs in other parts of Denmark except for the larger amount of bait, and less shrews and fruit. More than 80% of the diet of adult raccoon dogs in wetlands consisted of bait, birds (mainly ducks taken in autumn and songbirds), amphibians, carrion, berries, fruit, and grass. Also, insects (mainly larger beetles and aquatic insects) occurred in the diet of raccoon dogs in wetlands. Waterfowl eaten during the autumn and winter are likely to be migrating birds. A high number of carrion beetles and fly maggots indicates a high consumption of carrion of all kinds. Eggs of ground-nesting birds made up a negligible part of the raccoon dog's diet. eDNA-analysis found no trace of shorebirds and only common species of amphibians were recorded. This study provides no evidence that raccoon dogs are a threat to ground-nesting birds nor to endangered amphibians in Danish wetlands. [ABSTRACT FROM AUTHOR]

Ground‐nesting shorebirds must balance the need for acoustic communication at the nest with the constant threat posed by predators. Although it may seem likely that their calls are adapted to minimize detection by predators, little is known about how these birds communicate at the nest or whether they employ cryptic strategies to avoid predation. Using passive acoustic devices and software to analyse extensive acoustic data, we quantified and categorised the calls of black‐tailed godwits Limosa limosa limosa recorded throughout the whole incubation at eight nests at a dairy farm in the Netherlands in March–June 2021. While incubating, godwits frequently use five main call types, with distinct diurnal patterns and high variation in the number of calls between breeding pairs. Birds used two quiet calls, one for communication at the nest and a second without an easily suggested meaning. Three loud calls were presumably used for predator alert, territory establishment, and long‐range communication. Interestingly, although nests were close to each other and exposed to the same aerial predators, the involvement of incubating birds in predator alert calling consistently differed. Furthermore, we described the relationship between the number of predator alert calls and the probability of a godwit flying off the nest. Our findings show that incubating godwits predominantly use loud vocalizations during the day, with only a few calls at night, which were more frequent on nights with a full moon. These descriptive findings for a single godwit community should now be expanded to other contexts, experimental situations, and shorebird species. [ABSTRACT FROM AUTHOR]

For most rodent species, there is a lack of detailed studies of their diet to understand their predatory impact on other vertebrate taxa. For this reason, rodent predation on bird nests remains a largely unexplored field. Here we provide the first direct evidence, with the use of time-lapse video surveillance, that edible dormouse Glis glis depredated or attempted to depredate eggs and nestlings of two open-nesting passerine species, the Eurasian blackcap Sylvia atricapilla, and the common blackbird Turdus merula in a central European woodland. In the blackcap, we detected three predation events. In the first two cases, edible dormouse drove away incubating/brooding females and preyed upon either the eggs or the nestlings. The third case documents egg predation on an abandoned nest. In the blackbird, we document a single case of dormouse attacking a brooding female. The female and nestlings managed to escape. The fifth case documents an attempt to forage on eggs in an abandoned song thrush Turdus philomelos nest. Our observations provide evidence for dormice predation on passerine birds and highlight the value of direct nest surveillance for documenting rodent predation on birds. [ABSTRACT FROM AUTHOR]

For longer-lived species, individuals hedge their bets by skipping breeding when conditions are poor to preserve the opportunity for future breeding attempts. Thus, understanding the ecological drivers behind the 'choice' to reproduce or not is a key step in identifying and diagnosing causes of population change. We investigated both marine and terrestrial factors that might influence whether Kittlitz's Murrelets Brachyramphus brevirostris--a long-lived seabird of conservation concern that is often associated with glacially-influenced habitats--choose to breed in a given year. We used a suite of proxies to explain variation in reproductive metrics of radio-tagged Kittlitz's Murrelets, exploring three hypotheses related to prey availability, nest depredation risk, and energetic costs of nesting in Icy Bay, Alaska, 2007-2012. In two of the years, we compared results with the locally co-occurring, closely-related Marbled Murrelet B. marmoraus. Across the six-year period of our study, the posterior mean breeding propensity of Kittlitz's Murrelets was 0.21 (95% credible interval [CrI] = 0.15-0.27), nesting success was 0.41 (CrI = 0.25-0.57), and fecundity was 0.04 (CrI = 0.02-0.06). Although none of our three hypotheses were strongly supported by the data, our results collectively suggest that successful nesters expended greater effort than failed nesters and non-nesters to acquire sufficient prey--they stayed longer in the study area, had larger marine core use areas, spent slightly less time diving, and had shorter commuting distances and longer incubation shifts. Also, in years when fecundity was highest, overlap of individual marine core use areas was greatest, suggesting predictable foraging hotspots for murrelets in those years. Importantly, when comparing Brachyramphus species, we found that Marbled Murrelets outperformed Kittlitz's Murrelets reproductively by three to four times in overlapping years, suggesting different drivers of reproduction. From our collective results, we posit that the limitation to reproduction of Kittlitz's Murrelets may not be prey abundance or quality, but instead efficient access to prey. While our associations with indices of prey availability, depredation risk, and energetic costs to nesting did not explain much of the variation in fitness metrics, our study demonstrates the value of using a comparative approach and multiple metrics to diagnose factors limiting a population, especially when data are sparse. For bet-hedging species with complex life histories, we recommend using a combination of integrated modeling and a monitoring framework designed to accumulate evidence across studies to estimate population dynamics and improve inferences about ecological drivers. [ABSTRACT FROM AUTHOR]

Nest predation is typically the main cause of nest failure in forest understory birds; thus, identification of primary nest predators is key to understanding nest predation patterns. Furthermore, the responses of predators are likely affected by vegetation structure, but predator responses to micro-scale habitat characteristics are largely unknown, especially in tropical forests. We used a long-term study with one of the largest datasets of its kind to investigate the extent to which micro-habitat structure (5-m radius surrounding a nest) can predict the likelihood of predation and by which predator. In a secondary evergreen forest in northeastern Thailand, 2013–2021, we found 1,016 active nests of 13 species and 24-hour video-monitored 500 of them. We recorded 336 predation events from 16 nest predator species. From this and previous studies at our site, we identified the top 4 predator species/species groups accounting for ~83% of predation events: Macaca leonina (northern pig-tailed macaque, 36% of predation events), cat snakes (Boiga cyanea [green cat snake] and B. siamensis [gray cat snake]; 20%), Lycodon cf. davisonii (Blandford's bridle snake, 18%), and accipiters (Accipiter trivirgatus [Crested Goshawk] and A. badius [Shikra]; 9%). These 4 predator species differed in their responses to vegetation structure likely reflecting differences in foraging behaviors. Macaque and accipiters, both diurnal and visually oriented, tended to depredate more visible/open nests, but macaque depredated nests surrounded by more trees and short woody stems (<3 m tall) compared to raptors. For snakes, both nocturnal, cat snakes depredated nests with higher numbers of both short woody stems and woody climbers, whereas bridle snake depredated nests with more trees and fewer climbers. As noted previously, nest predator identity is critical to understanding habitat-predation patterns. Our data suggest that nest site vegetation characteristics influence the likelihood of a given species of predator locating a nest and that even small changes in vegetation structure could significantly alter predation patterns. [ABSTRACT FROM AUTHOR]

Greater sage‐grouse (hereafter sage‐grouse; Centrocercus urophasianus) populations have declined across their range. Increased nest predation as a result of anthropogenic land use is one mechanism proposed to explain these declines. However, sage‐grouse contend with a diverse suite of nest predators that vary in functional traits (e.g., search tactics or hunting mode) and abundance. Consequently, generalizing about factors influencing nest fate is challenging. Identifying the explicit predator species responsible for nest predation events is, therefore, critical to understanding causal mechanisms linking land use to patterns of sage‐grouse nest success. Cattle grazing is often assumed to adversely affect sage‐grouse recruitment by reducing grass height (and hence cover), thereby facilitating nest detection by predators. However, recent evidence found little support for the hypothesized effect of grazing on nest fate at the pasture scale. Rather, nest success appears to be similar on pastures grazed at varying intensities. One possible explanation for the lack of observed effect involves a localized response by one or more nest predators. The presence of cattle may cause a temporary reduction in predator density and/or use within a pasture (the cattle avoidance hypothesis). The cattle avoidance hypothesis predicts a decreased probability of at least one sage‐grouse nest predator predating sage‐grouse nests in pastures with livestock relative to pastures without livestock present during the nesting season. To test the cattle avoidance hypothesis, we collected predator DNA from eggshells from predated nests and used genetic methods to identify the sage‐grouse nest predator(s) responsible for the predation event. We evaluated the influence of habitat and grazing on predator‐specific nest predation. We evaluated the efficacy of our genetic method by deploying artificial nests with trail cameras and compared the results of our genetic method to the species captured via trail camera. Our molecular methods identified at least one nest predator captured predating artificial nests via trail camera for 33 of 35 (94%) artificial nests. We detected nest predators via our molecular analysis at 76 of 114 (67%) predated sage‐grouse nests. The primary predators detected at sage‐grouse nests were coyotes (Canis latrans) and corvids (Corvidea). Grazing did not influence the probability of nest predation by either coyotes or corvids. Sagebrush canopy cover was negatively associated with the probability a coyote predated a nest, distance to water was positively associated with the probability a corvid predated a nest, and average minimum temperature was negatively associated with the probability that either a coyote or a corvid predated a nest. Our study provides a framework for implementing an effective, non‐invasive method for identifying sage‐grouse nest predators that can be used to better understand how management actions at local and regional scales may impact an important component of sage‐grouse recruitment. [ABSTRACT FROM AUTHOR]

Breeding phenology can have strong demographic consequences. Yet, the reasons why coexisting animal species differ in breeding phenology have received little attention.We tested selection pressures that underlie life history variation, such as age‐specific mortality, diet, and body size to explain breeding phenology of 16 coexisting songbird species in arid shrubland in South Africa.The average start and end dates for the earliest and latest species differed by 1.5 months, with a gradient among remaining species. Nest predation risk generally increased through the season, although species differed in seasonal patterns. Species with lower annual adult mortality, greater seasonal increases in nest predation, and greater nest predation rates had earlier start and stop dates, thereby reducing demographic risks. Species with higher adult mortality had larger brood sizes that require more food and they bred later when food was more abundant. Evolved timing of breeding thereby reflected risk management and food availability related to longevity and brood size.These factors may place unrecognized constraints on within‐species responses to climate change. Given the importance of phenology for fitness, phenology should be integrated as a core life history trait in future theory, and evolutionary constraints need to be considered in responses to climate change. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Ground nesting birds have declined throughout Europe, with the reduction of habitat structure in agricultural areas being a key contributing factor. Habitat structure is vital not only for providing food and suitable microclimates for these species but also limits nest predation. Field assessments of habitat structure have, historically, been the most common way of identifying areas of low nest predation. However, they are limited in their applicability over wide areas due to time, money, and logistics. Remotely sensed measures (e.g., recorded by a satellite) can address these issues. Normalised difference vegetation index (NDVI) is a measure of the 'greenness' of an area and correlates with habitat structure. We conducted an artificial nest experiment over three years (2019, 2020, 2023) in Baden, Austria to test the relationship of NDVI to nest predation in an agricultural landscape. Critically, we compared whether NDVI could predict nest predation as well as locally recorded variables (ground cover, vegetation height, etc,). We report that NDVI performs equally well at predicting nest predation, with predation decreasing with higher values of NDVI, signifying greater habitat structure. This was supported by our finding that predation probability decreased with greater ground cover (a locally recorded variable). Additionally, we found that areas with greater partridge numbers had higher predation and circumstantial evidence that birds are the primary predator in our study area. Overall, our study shows that satellite-derived measures of habitat structure have untapped potential in identifying areas of high nest predation for European ground nesting birds in agricultural landscapes. [ABSTRACT FROM AUTHOR]

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Introduction: Multifarious selective pressures can interact to affect species' life history evolution, with predation and thermal exposure as selective pressures for nesting birds. Gray Vireos (Vireo vicinior) seemingly nest on the periphery of their nesting substrate because of lower predation rates, thereby increasing exposure to weather. We explored how nest placement and vegetation structure can be used to account for the increased weather exposure that Gray Vireos experience when nesting on the periphery of the nesting substrate to avoid predation. Methods: For each Gray Vireo nest, we placed temperature and light data loggers at three locations: at the nest site, at the opposite orientation of the nest within the nesting tree, and at the same orientation of the nest but in an adjacent tree. To measure nest orientation, we recorded the inverse compass azimuth (+/-1°) from the nest toward the trunk of the nesting tree, while accounting for declination. Nest temperatures and light exposure were compared across various dimensions of nest placement. Results: The orientation of nests was cooler than the opposite orientation in the mornings and in the late afternoons. When nests were placed in hotter orientations (e.g., south- or west-facing), nests surrounded by more foliage or placed closer to the interior of trees could compensate for the increased exposure. Discussion: Our findings suggest Gray Vireos accounted for the increased thermal exposure that comes from predator avoidance by using secondary dimensions of nest placement. Specifically, nests could be placed in orientations with cooler temperatures or in hotter orientations with greater shade potential. These results highlight how the interactive selection pressures of predation risk and microclimate can be tiered and shape life-history characteristics of birds. [ABSTRACT FROM AUTHOR]

We describe the predatory interactions between Neivamyrmex texanus (Watkins 1972) and the fungal-farming ant Trachymyrmex septentrionalis (McCook 1881) in central Texas and between Nomamyrmex esenbeckii (Westwood 1842) and its numerous species of prey, including the leaf-cutter ant Atta texana (Buckley 1860), in southern Texas. Species of the genus Neivamyrmex are generalist social insect predators that attack termites and a wide variety of species of ants, whereas Nomamyrmex are well-known specialists that evolved heavy body armor and fierce column raiding that is crucial for predation on the well-defended nests of the leaf-cutting ants in the genera Atta and Acromyrmex. We observed a marked difference in the response to the predation by army ants between the raids by Neivamyrmex on T. septentrionalis compared to those by Nomamyrmex on the colonies of A. texana. Our observations suggest that there are two distinct defense adaptations to the army ants. They include either making a stand and fighting, or absconding with the brood and garden, or so-called flight. [ABSTRACT FROM AUTHOR]

Bird-conservation organizations have long promoted the use of predator guards to increase nest success of cavity-nesting birds. Predator guards can effectively reduce nest predation, but lithium grease as a predator deterrent has never been tested. Therefore, our objective was to determine the effectiveness of lithium grease at increasing nest success. In 2017 and 2018, in Jonesboro, AR, we monitored nesting activity by Sialia sialis (Eastern Bluebird) in 148 nest boxes divided evenly among 3 treatments: baffle, grease, and no guard. Our results indicate that grease and baffles equally improved bluebird nest success by about 40%. Overall, lithium grease is a cheap and effective alternative to baffles that owners of bluebird boxes can consider using to increase bluebird nest success. [ABSTRACT FROM AUTHOR]

Parental investment increases offspring fitness at the expense of the parent's ability to invest in other offspring. In many animal species, parents guard their offspring after birth. The parental decision over the duration of this period is expected to be triggered by the associated fitness costs and benefits for both offspring and parents. Here, we evaluated the relevance of several intrinsic and environmental variables in determining brooding period duration in the wandering albatross (Diomedea exulans) and questioned whether brooding duration was related to chick subsequent survival and biometry prior to fledging. We used a semi‐experimental design to increase the variance in cat abundance, a recent predator of albatross chicks, and predicted that an increased predation risk at the nest scale would trigger longer chick brooding and thus, protection. In addition, we questioned the influence of weather conditions, hatching date, and characteristics of chicks (sex and biometry) and parents (sex and age) on brooding duration. We report no effect of predation risk or parental characteristics on brooding duration. However, the probability for a parent to end brooding decreased with forthcoming unfavorable weather. Our data also revealed reduced brooding duration for late‐hatched chicks and a positive association between brooding duration and chick structural size, and between the frequency of shifts between parents and chick structural size. Finally, brooding duration was not associated with chick survival or with chick biometry prior to fledging. We discuss these results in light of pre‐existing hypotheses on fitness costs and benefits associated with brooding duration for chicks and parents. [ABSTRACT FROM AUTHOR]

This article discusses a case of nest predation involving a Japanese Sparrowhawk and a Siberian Weasel in China. The researchers observed the weasel attacking the sparrowhawk and taking all of the nestlings and the remaining unhatched egg. The study highlights the vulnerability of small raptors to nest predation and its potential impact on their reproductive success. The document is a list of literature cited in a research article on various topics related to raptors, including breeding biology, nesting habits, and behavior, with studies conducted in different regions. The topics explored in the cited literature range from nesting failure to population decline and include aspects such as fearfulness, competitive interactions, migration routes, and parental investment theory. [Extracted from the article]

Small cell lung cancer (SCLC) is an aggressive pulmonary neuroendocrine malignancy featured by cold tumor immune microenvironment (TIME), limited benefit from immunotherapy, and poor survival. The spatial heterogeneity of TIME significantly associated with anti-tumor immunity has not been systemically studied in SCLC. We performed ultra-high-plex Digital Spatial Profiling on 132 tissue microarray cores from 44 treatment-naive limited-stage SCLC tumors. Incorporating single-cell RNA-sequencing data from a local cohort and published SCLC data, we established a spatial proteo-transcriptomic landscape covering over 18,000 genes and 60 key immuno-oncology proteins that participate in signaling pathways affecting tumorigenesis, immune regulation, and cancer metabolism across 3 pathologically defined spatial compartments (pan-CK-positive tumor nest; CD45/CD3-positive tumor stroma; para-tumor). Our study depicted the spatial transcriptomic and proteomic TIME architecture of SCLC, indicating clear intra-tumor heterogeneity dictated via canonical neuroendocrine subtyping markers; revealed the enrichment of innate immune cells and functionally impaired B cells in tumor nest and suggested potentially important immunoregulatory roles of monocytes/macrophages. We identified RE1 silencing factor (REST) as a potential biomarker for SCLC associated with low neuroendocrine features, more active anti-tumor immunity, and prolonged survival. [ABSTRACT FROM AUTHOR]

Wood ducks (Aix sponsa) are secondary natural cavity‐nesting species that also nest in artificial nest boxes. Since the early 20th century, nest boxes have been widely deployed in North America to increase nesting sites for wood ducks and bolster production. Equipping nest boxes with a predator guard beneath the box is a common practice to deter climbing predators from accessing boxes; however, there is no device to repel avian predators. We found that eastern rat snakes (Pantherophis alleghaniensis) and woodpeckers (Picidae) were primary predators of wood duck eggs in boxes in North Carolina and South Carolina. Accordingly, we designed experiments to deter snakes and woodpeckers using a commercial brand of snake repellent pellets and a plastic raptor decoy, respectively. Male and female snakes that accessed boxes averaged 1.4 m (SE = 2.0 cm) in length. Digital camera data indicated that snakes climbed nest box posts and thrust their anterior body atop predator guards to continue their ascent into the box. We recorded 671 nest failures of which rat snakes accounted for 39.9% (n = 268) and woodpeckers 22.4% (n = 150). Snakes consumed ≥649 eggs, observed as protuberances in their stomachs. Our experiment showed that commercial snake repellent pellets did not deter snakes (P = 0.957). Placing a plastic hawk decoy atop nest boxes when females were incubating ≥12 days increased nest survival during the incubation stage (P = 0.001). Wood duck nest boxes at our study sites may be experiencing increased nest predation by rat snakes due to poor maintenance and installation of predator guards. Rat snakes and woodpeckers may be depredating wood duck eggs in the southeastern United States at unknown rates, potentially decreasing production and recruitment from these structures. [ABSTRACT FROM AUTHOR]

Songbirds incidentally ingest soil contaminated with lead and several species in the Southeast Missouri Lead Mining District have a negative relationship between soil lead concentration and reproduction. We used an individual-based model (IBM) to simulate nesting processes throughout the breeding season to estimate annual productivity for 5 songbirds in relation to soil-lead concentration. We modeled daily nest survival and number fledged in relation to soil lead and incorporated these relationships into the IBM using a Bayesian approach that fully captured parameter uncertainty and process variation. The proportion of the posterior distribution for the effect of soil lead on daily nest survival was mostly negative for Pipilo erythrophthalmus (Eastern Towhee), Passerina cyanea (Indigo Bunting), Cardinalis cardinalis (Northern Cardinal), Sialia sialis (Eastern Bluebird; f = 0.972, 0.990, 0.741, 0.581, respectively), and slightly positive for Spizella pusilla (Field Sparrow; f = 0.680). The proportion of the posterior distribution for the effect of soil lead on the number fledged from successful nests was mostly negative for S. pusilla , P. erythrophthalmus , and C. cardinalis (f = 0.867, 0.585, 0.508, respectively) and positive for P. cyanea and S. sialis (f = 0.773, 0.744). Simulated annual productivity decreased by 0.04–1.47 young/female/year among species across the range of soil lead concentrations, with the greatest declines for P. erythrophthalmus and P. cyanea. The probability of fledging one or more young changed from 51% to 15% for P. erythrophthalmus , 57% to 23% for P. cyanea , 60% to 48% for C. cardinalis , 94% to 84% for S. sialis , and 57% to 64% for S. pusilla as soil-lead concentration around a nest increased from 20 to 4,000 ppm. Most nest failures were the result of predation; therefore, we suggest lead may have affected birds' behavior at the nest, or affected nest site quality, which resulted in higher nest predation. [ABSTRACT FROM AUTHOR]

In recent years, ecological research has become increasingly synthetic, relying on revolutionary changes in data availability and accessibility. In spite of their strengths, these approaches may cause us to overlook natural history knowledge that is not part of the digitized English-language scientific record. Here, we combine historic and modern documents to quantify species-specific nesting habitat associations of bumblebees (Bombus spp. Latreille, 1802 Apidae). We compiled nest location data from 316 documents, of which 81 were non-English and 93 were published before 1950. We tested whether nesting traits show phylogenetic signal, examined relationships between habitat associations at different scales, and compared methodologies used to locate nests. We found no clear phylogenetic signals, but we found that nesting habitat associations were somewhat generalizable within subgenera. Landcover associations were related to nesting substrate associations; for example, surface-nesting species also tended to be associated with grasslands. Methodology was associated with nest locations; community scientists were most likely and researchers using nest boxes were least likely to report nests in human-dominated environments. These patterns were not apparent in past syntheses based only on the modern digital record. Our findings highlight the tremendous value of historic accounts for quantifying species' traits and other basic biological knowledge needed to interpret global-scale patterns. [ABSTRACT FROM AUTHOR]

We report on a subfossil carpometacarpus of an extinct species of lapwing, Vanellus madagascariensis , restricted to Madagascar and inferred to be less than 3,000 years old. Lapwings, comprising 24 species in the New and Old World, are not recorded in the modern Malagasy avifauna. Members of this genus are often well-adapted to human induced habitat modifications. Material of this species has been recovered from three subfossil sites, each site with a single element, in the southwest of the island, including two humeri and a carpometacarpus. The carpal spur of V. madagascariensis was notably more developed than any living species of lapwing. It is presumed that these formidable armaments were employed to defend territories and hinder predation on nest contents and young. Large-scale desiccation in southwestern Madagascar starting about 3,000 years ago would have had a direct impact on local freshwater aquatic environments, in turn diminishing local habitat for this species, and ultimately leading to its extinction. [ABSTRACT FROM AUTHOR]

The recovery of mammalian predators of conservation concern in Europe is a success story, but their impact on some prey species of conservation concern may cause conservation dilemmas. This calls for effective intervention strategies that mitigate predator impacts without compromising their recovery.We evaluated diversionary feeding as a management intervention tool to reduce depredation on nests of rapidly declining Western capercaillies in Scotland. We studied the influence of diversionary feeding provision on the fates of artificial nests deployed using a replicated and representative randomised landscape‐scale experiment. This comprised 30 'paired' control (no diversionary feeding) and treatment (diversionary feeding applied) sites, 60 in total, each containing six artificial nests distributed across 600 km2. The experiment was replicated over 2 years, and in the second year, the control‐treatment pairs were reversed, yielding 60 treatment and 60 control sites and 720 artificial nests.Diversionary feeding substantially reduced depredation of artificial nests, translating into an 82.5% increase in predicted nest survival over 28 days of incubation. The increase in survival was mostly accounted for by a reduction in the probability that a pine marten, the main nest predator, consumed or cached eggs. Diversionary food also significantly reduced nest predation by badgers, although the magnitude of this effect varied by year.Synthesis and applications. Diversionary feeding is an easily employable method shown in this study to reduce predator impact (functional) without lethal (numerical) intervention. Managers should proceed with its application for conserving capercaillie in Scotland without delay. [ABSTRACT FROM AUTHOR]

The Bag‐shelter moth, Ochrogaster lunifer (Lepidoptera: Notodontidae), is an Australian endemic species of Thaumetopoeinae with a univoltine life cycle and gregarious, herbivorous larvae. It is variable throughout its range across the continent, most noticeably by the species of host tree used and nest‐building behaviour. It has long been considered a species complex by some taxonomists, and the lack of gene flow between populations of ground‐nesters and above‐ground nesters at the same sites provides strong evidence for at least two species. We tested the specificity of host use and nesting behaviour of ground‐nesting and trunk‐nesting forms of O. lunifer by transplanting field‐collected egg masses to the other form's host, either in their natural position or in the position used by the other form. At the study site, ground‐nesting and trunk‐nesting (tree‐hugger) O. lunifer coexist. Ground‐nesting larvae are found on Acacia spp., and egg masses are laid at the base of host tree trunks where nests develop whereas tree‐hugger larvae are found on Blakella tessellaris, egg masses are laid in the outer canopy, and nests develop on the trunk or large branches. Of the 47 egg masses of O. lunifer transplanted to the unnatural host, only one cohort of tree‐hugger larvae developed through to adult moths. Placing an egg mass in its unnatural position on its natural host did not prevent the larvae from developing and successfully establishing nests for either nesting‐form, although all the ground‐nesters moved position (from the canopy to the ground) and the tree‐huggers mostly did not (from the ground to the canopy). Only the tree‐hugger form of O. lunifer developed a viable nest on the unnatural host species, established a nest at the unnatural oviposition site, and shared that nest with larvae of the other nesting‐form, suggesting tree‐hugger larvae are somewhat plastic in their behaviour and ecology. Our findings add to previous studies indicating that Acacia is likely the ancestral host of O. lunifer though large areas of its range remain unstudied. [ABSTRACT FROM AUTHOR]

The presence of domestic animals in the wilderness has a negative effect on wildlife populationsor; for instance, in addition to habitat loss, urbanization, and coastal light pollution, sea turtles also suffer from another threat: the predation of their eggs, hatchlings, and even female nesters by domestic, feral, and/or wild animals. Domestic dogs are a considerable concern for turtles in nesting areas, due to their free-ranging lifestyle and the absence of predators. This study sought to evaluate the nest density and rates of sea turtle predation caused mainly by canids: foxes (native predator) and dogs (introduced predator) in the nesting areas of Southern Bahia, Brazil. Predation data was collected during field surveys and by using camera traps and hair traps installed in nests. During the sampling period, an average of 46 nests were laid by three sea turtle species: Caretta caretta, Eretmochelys imbricata, and Lepidochelys olivacea; 46.4% were lost due to predation or inundation caused by the tides. Canine populations on the island have an evident impact on sea turtle nests. Thus, it is crucial to design and implement environmental education programs and management plans with the local community to help reduce human-made and natural loss of nests and safeguard sea turtle populations and their habitat. [ABSTRACT FROM AUTHOR]

Nest predation is the leading cause of reproductive failure in birds and a major driving force in the evolution of anti-predation strategies. Current studies on the anti-predation strategies of birds driven by predation pressure have mainly focused on adults. However, the detection and behavioral responses of nestlings toward predation risk require further investigation. In this study, we examined nestling responses to predator sounds. Two species of nestlings, the Reed Parrotbill (Paradoxornis heudei) and Vinous-throated Parrotbill (Sinosuthora webbiana), were exposed to the Sparrowhawk (Accipiter nisus, less common) and Oriental Magpie (Pica serica, more common), which are predator species, the Oriental Turtle Dove (Streptopelia orientalis), which is a commonly found harmless species, and background noise. Our findings revealed that compared to pre-playback of natural begging and playback of background noise and Oriental Turtle Dove sounds, playback of the two predator types decreased the total begging time and total number of calls of the two nestlings species, with the calls of the Sparrowhawk leading to greater suppression of nestling begging behavior than those of the Oriental Magpie. Therefore, our results indicated that these nestlings were able to distinguish predators from harmless species based on auditory cues.

The nesting habits of Baya Weaver Ploceus philippinus with nesting site (e.g., power and television cables), source of nest materials, various developmental stages of nests, abnormal nests, number of individuals and their association with other bird species, and threats to their nests were studied between March and September 2021 in the agrarian landscapes of 42 villages in Kallakurichi District, Tamil Nadu. A total of 155 nest colonies containing 1,725 nests of various developmental stages and 1,993 adult birds were counted on power/television cables. The number of nests per colony found varied from one to 57. The average number of nests per colony was eleven. Baya Weaver had preferred power/television cables as nesting sites in the study area in spite of availability of potential nest-supporting trees, such as Cocos nucifera and Borassus flabellifer within 500 m radii from cables bearing nests. Birds used fibres of sugarcane leaves (Saccharum officinarum) for the construction of nests. Out of 778 helmet stage nests observed, 90% (n = 716) helmet stage nests had clay deposits on their inner walls and no clay deposits were found in the remaining 10% (n = 62) helmet stage nests. Eleven types of abnormal nests constituted 17% (n = 286) of the total nests. Sixteen other bird species (e.g., birds of order: Passeriformes, Coraciiformes, Piciformes, Cuculiformes and Columbiformes) were found associated with the individuals of Baya Weaver. These bird species strictly shared similar roosting and foraging grounds. The avian predators such as House Crow Corvus splendens, Large-billed Crow Corvus macrorhynchos, Black Drongo Dicrurus macrocercus, Rufous Treepie Dendrocitta vagabunda, Coucal Centropus senegalensis, and Shikra Accipiter badius had damaged the nests, eggs and chicks. The study revealed that about 1.1% nests (n = 197) were probably damaged by these avian predators. Power cables in the study sites had provided suitable nesting sites for Baya Weavers. The causes for utilization of power cables as nesting sites in larger geographical areas require further studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Predation is one of the most important factors shaping birds' reproductive strategy. For species nesting in the valley of a large lowland river, flooding is also an additional risk, which can significantly reduce nesting success. During this study, we examined what factors affect the nesting survival of the common sandpiper, a small wader species that inhabits waterbodies, especially rivers. Nests located under shrubs were significantly less predated than nests built in grass. Also, locating nests close to water increases the probability of nesting survival. Predation increases as the breeding season progresses, while nests were most vulnerable to flooding at the beginning of the season. The results obtained in this study provide a better understanding of the factors limiting the nesting success of birds breeding in river valleys and can be the basis for planning conservation measures to increase the nesting success of riverine birds. Predation is an important factor limiting bird populations and is usually the main factor influencing nest survival. In riverine habitats, flooding poses an additional significant challenge. Our study aimed to elucidate the influence of nest location and incubation timing on the survival of common sandpiper nests in a large, semi-natural, lowland river. The survey was carried out in central Poland on the Vistula River, in 2014–2015, 2021, and 2023, along two river sections 2 km and 10 km in length. The nest survival rate was 27%, which is twice as low as that reported on small upland rivers, with flooding being an additional factor causing losses on the Vistula River. Our research showed that mammalian and avian predation accounted for 51% of losses and flooding for 49% of losses. The negative impact of floods on nest survival decreased as the breeding season progressed between May and July, while the chances of being depredated increased during the same period. Nests placed under shrubs were less likely predated than nests located in grass. Moreover, locating the nest in proximity to water increased nesting survival and in fact, more nests found in our study were situated close to the water's edge. [ABSTRACT FROM AUTHOR]

Many habitat-specialist organisms occur in distinct, patchy habitat, yet do not occupy all patches, and an important question is why apparently suitable habitat remains unoccupied. We examined factors influencing patch occupancy in near-threatened, little-known Diademed Plovers (Phegornis mitchellii), arguably the bird most specialized to life in High Andean peatlands. Andean peatlands are well-suited to occupancy modelling because they are discrete patches of humid habitat within a matrix of high-altitude steppe. We hypothesized that Diademed Plovers occupy preferably larger and more humid peatlands, and avoid peatlands used for grazing by llamas and vicuñas, which may trample vegetation and nests. From December 2021 to February 2022 (breeding season), we conducted plover occupancy surveys (2–4) on 40 peatlands at Lagunas de Vilama, a landscape of arid steppe and wetlands above 4,500 m in NW Argentina. We measured peatland size, grazing pressure, topographic and remotely-sensed variables that correlate with humidity, and incorporated these as covariates in occupancy models. Occupancy models showed that more than 50% of the studied peatlands were used by Diademed Plovers and most showed signs of reproduction, highlighting the importance of the Vilama Wetlands for Diademed Plover conservation. Within peatlands, Diademed Plovers were most often associated with headwaters. The top ranked occupancy model included constant detection, random spatial effects, and a single occupancy covariate: mean NDWI (Normalized Difference Water Index, an index correlated with water content and humidity) over the previous three years. Contrary to our prediction, Diademed Plovers preferred less water-saturated peatlands (lower NDWI), possibly to avoid nest flooding. This may be especially important in wet years, like the year when we conducted our surveys. Neither peatland size nor grazing by llamas and vicuñas affected peatland use by Diademed Plovers, suggesting that llama grazing at current levels may be compatible with plover conservation. For organisms that specialize on humid habitats, such as peatlands, factors affecting occupancy may vary temporally with variation in climate, and we recommend follow-up surveys across multi-year timescales to untangle the impact of climate on animals' use of humid habitats. [ABSTRACT FROM AUTHOR]

Given the critical role of temperature in avian reproduction, rising global temperatures will likely impact reproductive success of many bird populations. We examined the effect of nest box temperature, nest box color, entrance orientation, distance to forest cover, and distance to water on nest box selection, nest success, and nestling size in eastern bluebirds (Sialia sialis) in central Georgia. White painted nest boxes had significantly cooler temperatures than control nest boxes (P < 0.05). However, model selection revealed that eastern bluebird females selected control boxes, despite their overall warmer temperatures. Nest success was associated with year, likely because of high nest predation during the warmer 2022 breeding season (P < 0.05). Nest success was also associated with cooler nest boxes, possibly because females spend more time on the nest to warm it which can reduce predation risks. Larger nestlings fledged from painted nest boxes, nest boxes with cooler temperatures, and nests from 2021, which we attribute to decreased thermoregulatory demands enabling faster nestling growth in cooler boxes and years. These seemingly opposing results suggest there may be an optimal temperature range where nest box temperature maximizes reproductive fitness while minimizing energetic demands on incubating adults. Determining this temperature range can help target management efforts to ensure specific goals are met. [ABSTRACT FROM AUTHOR]

Due to rapid homogenization in habitat types as a result of urbanization, some urban birds adapt their nesting strategies to changes in local habitat characteristics. Bird nesting decisions might have been mainly linked to resource constraints and ensuring reproductive success. In this study, we examined patterns of nesting behavior by spotted doves (Spilopelia chinensis) in a rapidly urbanizing area of Nanchang, China using ArcGIS 10.8, satellite tracking, camera traps, and field survey. To explore the mechanisms underlying nesting behavior in urban habitats, we assessed the correlations between nest reuse and reproductive success, and between nest reuse and nest predation. From December 2018 to December 2021, a total of 302 breeding nests were surveyed. The results revealed that the nest reuse rate was 38.08% (n = 115). Nests closer to trunk, with lower nest position and higher large‐scale urbanization score tended to have higher reuse rate. In addition, nests with the higher the nest height and percent of canopy cover, and the lower small‐scale urbanization score were more likely to reproduce successfully, and the reused nests also reproduce more successfully. The reproductive success associated with nest reuse was significantly higher than that associated with new nests (χ2 = 8.461, p =.004). High degree of urbanization promoted nest reuse of spotted doves (large‐scale urbanization score, z = 2.094, p =.036), which apparently enhanced their reproductive success (nest reuse, z = 2.737, p =.006). In conclusion, a nest structure with good permeability is the material basis for the nest reuse in spotted dove, while the relatively low risk of predation in urban habitat and the scarcity of nest site resources due to urbanization increase the tendency of birds to reuse old nests, which is associated with their reproductive success and evolutionary fitness. [ABSTRACT FROM AUTHOR]

Alternative reproductive tactics enable individuals to choose a reproductive tactic relative to their status and prevailing environmental conditions in a way that increases their fitness. For example, females in many avian species show phenotypic plasticity and employ alternative reproductive tactics to cope with changes in predation risk and climate. Conspecific brood parasitism (CBP), in which females lay eggs in nests of conspecifics, is one example of such behaviour. It has been proposed that when prospects for successful nesting are low and/or costs of reproduction are high, females employ tactics of low effort such as non‐breeding and parasitic laying. When environmental conditions are ideal and prospects for success high, females can increase their reproductive effort above typical nesting by laying parasitic eggs prior to initiating their own nest. Here, I used this flexible life‐history strategy concept and long‐term (1994‒2022) population level data of the common goldeneye Bucephala clangula to study how the rate of parasitic laying varies in relation to variation in nest predation risk and in the timing and length of the breeding season, the latter being measured by the timing of ice breakup. Nest predation rate in the previous year and timing of ice breakup interactively affected parasitic laying, the rate of parasitic laying being particularly high in years with late ice breakup and high nest predation rate in the previous year. Furthermore, the proportion of predated eggs was lower in parasitized nests than in non‐parasitized nests, while the opposite was true for the proportion of eggs that failed in other way. As a consequence, the final number of young produced per nest was higher for parasitized nests. The findings of this study show that changes in environmental conditions affect the dynamics of alternative reproductive tactics in goldeneyes, with consequences to population level reproductive output. [ABSTRACT FROM AUTHOR]

Ecological and social factors shape individual reproductive strategies. Climate change has wide‐ranging effects on the timing of reproduction and availability of nesting sites for many birds. Ecological factors such as season length or predation rate could in turn affect the relative success rates of alternative reproductive tactics (ARTs). A new article by Pöysä (2024) featuring a long‐term study of common goldeneyes Bucephala clangula highlights the role of climate change in altering rates of conspecific brood parasitism (CBP) by affecting nest initiation dates and season length. While some authors have emphasized the effects of spatial and temporal aggregation of nests in promoting tactics of reproductive interference, few studies have addressed the effects of environmental variables on rates of CBP and other ARTs. I review some of the evidence for a relationship between population‐level nest predation rate and rates of CBP, principally in ducks and rails, and suggest a role for high rates of nest loss from all sources in the evolution of CBP and host responses. There is a need for further studies that examine environmental correlates of ARTs. Long‐term studies have the highest potential to reveal how shifts in phenology and life history variables may respond to environmental perturbations. Comparative studies of similar species in remote geographic locations can add perspective of how different ecological variables affect the prevalence of ARTs. [ABSTRACT FROM AUTHOR]

Nest-site selection is a behavioral response that can provide protection for adults, eggs and nestlings, affecting fitness. Since predation is the main cause of nest loss worldwide, it has been considered as the main evolutionary driver in nest-site selection. Nevertheless, in some cases, nest microclimate may be the primary evolutionary force operating on nest-site selection. We aimed at determining at mesohabitat and microhabitat scales if Chilean Elaenia (Elaenia chilensis) selected the nest site and, if so, whether such selection was associated with a reduction in nest predation. Since nest orientation may influence nest microclimate, we also tested whether it affected the reproductive output. At the mesohabitat scale, the subcanopy cover (1.5–4 m from the ground) was selected by this species. At the microhabitat scale, elaenias preferred Schinus patagonicus to nest and oriented their nests preferentially to the north and eastern directions. These selected habitat features had no effect on nest success and reproductive output. Despite the risk of nest predation by several aerial (birds) and ground predators (rodents), both successful and predated Chilean Elaenia nests were close to the ground rather than at intermediate heights. Considering the hardness of S. patagonicus wood that can provide structural support to the nest against strong winds, and that nests were oriented to the opposite direction of prevailing wind, Chilean Elaenia nest-site selection might be related to microclimatic factors at nest sites rather than predation. Therefore, it is imperative to consider potential associations between nest microclimate and habitat features to advance in the understanding of bird nest-site selection. [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]

Numerous Woodchat Shrike (Lanius senator) populations, and Laniidae in general, are globally declining. A deeper understanding of their breeding ecology, including their nest-site selection and breeding performance, from hatching success to post-fledging survival, could contribute to their conservation. We studied breeding Woodchat Shrikes near the southern edge of their breeding range in Northern Israel, monitoring breeding pairs throughout the breeding season from March to July 2023 in three study areas at the slopes of the Golan Heights in a semi-open shrubland. We collected data on birds' nesting success, including hatching and fledging success, as well as on breeding pairs' productivity and post-fledging survival of Woodchat Shrikes. Furthermore, we gathered information on nest-site characteristics. In this part of their range, Woodchat Shrikes breed in relatively high densities, opportunistically selecting nest-sites within the area. Most pairs had at least two brood attempts and up to four were recorded. On average breeding pairs laid 4.63 eggs per brood, with a decreasing brood size later in the season. Breeding performance was not related to the nest-site characteristics with the exception of nest height above the ground, which had a positive influence on nesting success. The breeding performance of Woodchat Shrikes was relatively low compared to other studies, particularly when considering fledging success. Nest predation was likely a predominant cause for nest failures here; however, breeding pairs were able to substantially increase their breeding success with replacement broods. Compared to the low nesting success, the post-fledging survival was relatively high, indicating much higher predation pressure on nests compared to fledglings. [ABSTRACT FROM AUTHOR]

Competition within and between species affects community structure and is well documented in raptors. We investigated the spatial distribution of two sympatric raptors in Cyprus, the Bonelli's Eagle (BE) and the Long-legged Buzzard (LLB). Both species are facultative tree/cliff nesters, with overlapping nesting and foraging areas. In 2021, the BE population consisted of 40 pairs with a density of 1,3 pairs/100 km2, and the LLB population of 113 pairs with 2,9 pairs/100 km2. About 80% of BE nesting sites and 43% of LLB nesting sites were situated within the Natura 2000 (N2K) protected areas network while 97% of BE nesting sites and 91% of LLB's were situated within 2.5 km from N2K areas. The spatial distribution was compared between and within species based on Nearest Neighbour Distance (NND) analysis. Average intraspecific NND for BE was 6.158 ± 2.207 m (SD), almost double compared to LLB which was 3.151 ± 1.730 m (SD). The distribution of BE nesting territories showed a regular spacing, indicating a stronger effect of intraspecific competitive interactions, whereas LLB nesting territories did not differ significantly from random. Average interspecific NND for BE was 5.339 ± 3.719 m (SD) and for LLB 5.673 ± 3.931 m (SD). Only the LLB had a regular pattern, suggesting that LLB pairs take into account neighbouring BE active territories when establishing their own, while the opposite is not the case. Therefore, the LLB, which is the smaller of the two raptors, avoids BE nesting sites by placing its nests further than to conspecifics. NNDs in 2021 were lower compared to previous studies in Cyprus, in 2005 for LLB and 2009 for BE, indicating an increase in both species' densities. [ABSTRACT FROM AUTHOR]