Ibis

Sentinel behaviour occurs when individuals use raised positions to scan for predators while the rest of the group forages. Here, we investigated whether a colonial cooperatively breeding species that forages in large groups, the sociable weaver, Philetairus socius, displays sentinel behaviour. This behaviour has been reported in species with similar ecology, behaviour and foraging habits, (e.g. ground foraging in open habitats where aerial predators are common) and, hence, we expected that it could occur in sociable weavers. On the other hand, sentinel behaviour appears to be less common in species that live in very large groups. We used an experimental set-up consisting of an artificial feeding station and perches to assess occurrence of sentinel related behaviours: (i) perching events > 30s on an elevated position, (ii) head-movements and (iii) alarm calling. Birds were seldom observed perching while others fed, and those that did, perched for periods that were too short to be considered as sentinel behaviour (less than 5s on average). Our results suggest that this behaviour is uncommon or even absent in sociable weavers. We discuss whether other factors such as foraging in very large groups, or interspecific foraging associations might make sentinel behaviour less important in this species.

Island populations are special for the study of evolutionary processes and can be a zone of incipient speciation. Recently, several island populations of House Wren in the Lesser Antilles (Dominica, St Lucia, St Vincent, and Grenada), formerly recognized as subspecies of the continental form, were reclassified as distinct species. However, much of the supporting data was fragmentary in its sampling of the different islands or equivocal in the patterns observed. Because song is a core element of mate recognition and choice, and can therefore be a key character in species identification, I report here the first detailed characterization and analysis of song for House Wren on all of the islands of the Lesser Antilles where they remain, including Trinidad and Tobago; and compare song patterns across the different islands as well as to several continental populations. Results show that song is broadly similar across all of the islands and to continental populations in high-level features of its structure, organization and delivery but is discriminably different among many of them in its more detailed features. The latter differences are consistent with the recent species splits, with the possible exception of Grenada. They also support retention of House Wren on Trinidad and Tobago as subspecies of the continental form. Results also point to the possibility of a central American origin for some of the islands and a south American origin for others, yielding a trait mosaic where islands that putatively share the same geographic origins, and are therefore presumably genetically closest, are not the most similar in patterns of song (or plumage). This pattern would therefore entail multiple intriguing instances of convergent evolutionary divergence among them that warrants further detailed study. Lay SummaryO_LII provide the first comprehensive analysis and comparison of song patterns of House Wrens for all of the islands of the Lesser Antilles where they remain, some of which are at risk of extirpation, or even extinction if they represent distinct species. C_LIO_LII use the patterns to interpret the recent taxonomic reclassification of many of these island populations as distinct species. C_LIO_LIIn their general structure, organization and delivery male song is similar across all of the islands and follows patterns common to contintental forms of House Wren distributed broadly across North, Central and South America. C_LIO_LISongs of the different islands are, however, discriminably different in their more detailed features and these differences are consistent with most, but possibly not all, of the recent species splits. C_LIO_LIFor the island populations recently reclassified as different species, the distinctiveness of male song is greatest in Dominica and St Vincent and to a lesser extent also St Lucia, and least distinctive in Grenada. Song in Trinidad and Tobago is not substantively different from populations in mainland South America which supports retaining these two island populations as subspecies of the closest continental forms. C_LIO_LISong patterns also point to different possible continental sources for some of the island populations: a source in Central America for Dominica and St Lucia; and a source in South America for the rest. If true, this creates multiple instances of convergent evolutionary divergence in trait patterns across the various islands which merits further study. C_LI

Island endemic birds are under greater threat than their mainland counterparts. Sedentary living and historically reduced predation may affect island bird sociality and inform their conservation and management. However, detailed studies on their sociality are uncommon. The federally- endangered koloa maoli (Anas wyvilliana, Hawaiian duck, or koloa) is primarily threatened by hybridization with feral mallards and avian botulism outbreaks. We used capture-mark-recapture and genetic data on koloa on the island of Kaua i, a stronghold of remaining koloa, to construct social networks and examine their associations (inferred from co-occurrence in traps) and spatial genetic structure. Information on associations might shed light on preferences for or against mallards and hybrids, and inform planned translocation efforts. Microgeographic spatial genetic structuring where relatedness among individuals scales with geographic distance is a potential liability for maintaining koloa genetic diversity, and would particularly be detrimental during highly localized outbreaks of botulism that could result in the removal of entire lineages. While we found persistent social associations among adult koloa, they were not apparently influenced by plumage traits or body mass, suggesting a lack of social preference for mallard-like individuals. Importantly, we found no spatial patterns of relatedness within the largest refuge. Therefore, botulism outbreaks remain a demographic threat but are unlikely to remove correlated genetic diversity. There were no sex differences in spatial genetic structure and both sexes moved within a refuge. The lack of spatial genetic structure and the presence of many unrelated conspecifics may enable koloa to limit inbreeding and retain genetic diversity without sex-biased dispersal. In the context of future translocations, our results suggest that translocating koloa captured in the same trap together will reduce disruption of preferred associations while also retaining genetic diversity among translocated individuals. LAY SUMMARYO_LIThe koloa maoli (Hawaiian duck, or koloa) is a federally-endangered, island endemic bird. Like other Hawaiian waterbirds, koloa are threatened by introduced predators and habitat loss, but also specifically by hybridization with feral mallards and localized avian botulism outbreaks. Currently, the island of Kaua i has the largest population of non-admixed koloa. We used capture-mark-recapture and genetic data of koloa at two wetland sites on Kaua i to examine their sociality and spatial genetic structure. C_LIO_LIKoloa formed preferential social associations, but they were not based on plumage traits, body mass or genetic relatedness. C_LIO_LIThere was no spatial genetic structure for males and females within a wetland site. Our results suggested that 1) koloa have no preference for mallard-like plumage that might increase hybrid pairing, 2) localized (within-refuge) botulism outbreaks are unlikely to remove close relatives and unique genetic lineages, and 3) translocation of groups could maintain social associations without limiting genetic diversity. C_LI

In cryptic or difficult-to-detect bird species, the monitoring schemes based on generalist detection methods may introduce bias into abundance estimates and population indices. This the case of the Coturnix coturnix (Common quail), a migratory Palearctic galliform, in which the use of passive detection methods within breeding birds monitoring schemes may not be efficient owing to its complex socio-sexual system and migratory behavior. For the first time, C.coturnix detectability was simultaneously compared using standard passive, generalist multispecies survey methods from the Pan-European Common Bird Monitoring Scheme (PECBMS) and a species-specific active survey employing female call playback. Surveys were conducted at 1,077 listening points within 107 transects over four breeding seasons (2022-2025) in open farmland landscapes dominated by cereal crops in Extremadura, south-western Spain. Detection counts differed substantially between methods: active surveys increased expected counts by 72% (95% CI: 59-85%) compared to passive surveys. The increase in C.coturnix detections elicited by playback showed a non-linear, density-dependent pattern, being highest at low passive abundances per listening point (maximum at 3-4 individuals) and stabilizing at intermediate abundances. This indicates that call playback is particularly effective at detecting individuals that would otherwise remain undetected. Our findings suggest that passive, multispecies surveys may underestimate C.coturnix abundance, especially in low-density populations. Integrating species-specific active methods into monitoring programs can improve detectability, generate more reliable population indices, and support evidence-based conservation and management strategies for this elusive species. LAY SUMMARYO_LIBird monitoring schemes guide conservation decisions across Europe, but generalist schemes based on passive methods may miss species that are hard to detect such as C.coturnix Common quail, a migratory farmland bird that hides in dense crops. In practice, only males spontaneously calling can be detected, hence passive methods could lead to underestimates of its abundance and even false absences in low-density areas. C_LIO_LIWe compared standard passive surveys with surveys that added a recorded female call (playback) to stimulate male responses. Across 1,077 listening points monitored over four breeding seasons in southwestern Spain, playback increased the number of birds detected by 72% compared with passive methods alone. C_LIO_LIThe improvement was strongest where C.coturnix numbers were low, showing that many individuals remain undetected without playback. Incorporating simple, species-specific methods into monitoring programs can produce more reliable population estimates and strengthen conservation and management decisions for this elusive species. C_LI

The tail of birds contributes substantially to flight aerodynamics through lift generation, reduction of pressure drag, and pitch stabilization. Hummingbirds are powerful flyers, able to sustain hovering in still air, generate lift in both the up- and downstroke, and takeoff due to substantial developmental investment in their wings and corresponding musculature. Given the abundance of wing power, it is possible that tails are less essential to the aerodynamics of hummingbird flight than they are in other birds, freeing them for non-locomotor functions. Hummingbird tails are well known for their morphological elaboration as sexually selected ornaments, including sound generation. Our observations, and brief descriptions in the literature, led us to hypothesize that tail flaring may serve as another form of sexual signaling, used by males during male-male fighting. To test this, we used high-speed video to record agonistic encounters among seven species of hummingbird the field and found 95% of inter- and intra-sexual and specific contests included tail flaring. We measured kinematics of this flaring during male-male fighting of calliope hummingbirds (Selasphorus calliope, n = 5) indoors. Consistent with our hypothesis, captive males exhibited greater angles of tail flare when engaged in a fight (26.9 {+/-} 42.9{degrees}, mean {+/-} sd) than when performing solitary landing (-12.7 {+/-} 8.6 {degrees}) and takeoff (-11.1 {+/-} 6.6 {degrees}) maneuvers. We evaluate these results in the context of signaling during animal contests and propose future tests of whether tail flaring is an honest signal of individual quality and Resource Holding Potential (RHP). Summary StatementMale-male fighting is common in hummingbirds with competition over food and mates. During these competitions, tail flaring and waggle maneuvers are used as a signal of aggressive intent.

Cross-Fostering, i.e., the exchange of eggs or hatchlings, is a widely used technique, to disentangle genetic from environmental effects or to manipulate the clutch size. In most bird species, this manipulation is easily accepted by the social parents, leading to the conclusion that fostering has no detrimental effect. Using a dataset of four cohorts (N=298) of zebra finches (Taeniopygia castanotis), in which we fostered routinely a single egg into another nest of zebra finches, we explored potential short- and long-time effects of fostering. Noteworthy, these experiments were not designed to test this hypothesis. The objective of the egg fostering experiments was to test for parental recognition (Caspers et al. 2017) and mate choice decisions (Goluke 2018). Consequently, the aim of the present study is purely explorative. Our study confirmed previous findings that fostering has no short-term effects on the morphology and growth rates of the chicks, neither in males nor in females. However, we found that fostering has a sex-specific long-term effect. Females originating from fostered eggs had a significantly reduced lifespan compared to those from non-fostered eggs. Conversely, the lifespan of fostered males was similar to that of non-fostered males. All birds were housed in large groups, experiencing the same conditions after nutritional independence (day 35). Therefore, we can only speculate that fostering might result in early developmental stress, which may affect the individual fitness of females later in life, ultimately leading to shorter lifespans.

BackgroundVolubility, the number of vocalizations per unit of time, is a relatively understudied aspect of animal communication, potentially crucial in highly social systems like cooperative breeders that depend on coordinated behavior. Callitrichid monkeys, including common marmosets (Callithrix jacchus), are often characterized as highly vocal, yet the variation in their calling rates due to context or individual differences remains poorly quantified. In this study, we systematically examined captive marmoset volubility across different social and informational contexts, call types, and individual characteristics. ResultsWe tested marmosets in dyads in different experimental conditions and recorded a total of 70,260 vocalizations. Overall, calling rates were not influenced by sex or status. Instead, volubility varied mainly with condition: rates increased when visually separated from the partner and individually encountering ecologically salient stimuli such as ambiguous objects or food, consistent with context-sensitive signaling and information asymmetry. Contact calls were more frequent in food-related contexts, indicating a recruiting function. Arousal calls were strongly predicted by age, with younger individuals calling more, especially when confronted with an ambiguous object. Food calls occurred almost exclusively during direct interactions with food, particularly during feeding. Dyadic analyses revealed covariation between callers and partners arousal calls, consistent with vocal contagion. In contrast, we found no contagion effects for food calls. Instead, food calls by a breeder encountering food increased contact calling in their naive dyad partners. ConclusionsOverall, marmoset volubility is flexible and call-type-specific, shows signatures of information sharing under information asymmetry, and highlights their nuanced communication strategies.

Acoustic signaling is key to individual and species recognition, playing a major role in sexual and social communication. Since reproductive isolation is often maintained through pre-mating mechanisms, song can be an early isolating trait leading to assortative mating, promoting reproductive divergence, and potentially contributing to speciation. However, whether song differences alone are sufficient to prevent interbreeding or if other traits also contribute, remains a matter of debate. Playback experiments provide a more direct way to test the role of song as a reproductive barrier. Here, we use playback experiments to test the hypothesis that song acts as a pre-mating barrier in two recently diverged populations of an island passerine, the Canary Islands Chaffinch (Fringilla canariensis palmae), which inhabit ecologically distinct laurel and pine forests within the island of La Palma. Assuming that male song has diverged in the two habitats, we tested if territorial males from a given habitat responded differently to songs from intruding males from their own habitat or from the other habitat type, using a closely related mainland species as a control. We found that probability of response was weaker to songs of the closely related species and to the different-habitat birds than to songs of the same-habitat birds, but differences for the latter were weak. The intensity of response followed the same pattern. Overall, song divergence between laurel and pine forest chaffinches does not appear strong enough to cause clear behavioural discrimination against individuals from the alternative habitat. Other factors such as morphological and ecological divergence associated with adaptation to local resources might better explain population differentiation. However, testing female responses will be essential to determine whether songs convey lineage-specific information that may elicit assortative mating.

Natural history collections underpin our understanding of species distributions, yet some historical records remain embedded in modern avifaunal checklists despite limited documentation and no independent verification. One such case concerns the Dusky Parrot Pionus fuscus in Colombia: although reported from specimens collected by Melbourne A. Carriker Jr. in 1942 in the Serrania de Perija, the species has not been observed in the country for nearly eight decades yet continues to be included in national checklists and conservation assessments. We reassessed the validity of this record by applying a multi-evidence framework integrating historic archival reconstruction, specimen-based morphological comparisons, climatic niche analyses, biogeographic limit assessment and contemporary survey-effort data. Historical documentation and morphological evidence based on high-resolution specimen images and associated curatorial records demonstrate that the Carriker specimens correspond to Pionus chalcopterus, not P. fuscus. Climatic niche analyses reveal minimal environmental overlap between P. chalcopterus and P. fuscus, and place the Perija locality within the climatic niche of P. chalcopterus, while regional biogeography and extensive modern birdwatching coverage provide no support for the occurrence of P. fuscus in Perija. Together, these concordant lines of evidence demonstrate that P. fuscus does not occur in Colombia. Our findings support its removal from national bird lists and conservation assessments and highlight how integrated, multi-evidence reassessments of historical records strengthen ornithological baselines, improve biogeographic inference and ensure that conservation priorities rest on verifiable evidence.

Habitat structure, food availability, and predation risk have spatiotemporal variation on the landscape that creates tradeoffs between risk and rewards for animals as they use habitat. These tradeoffs are associated with survival consequences and can vary by life or breeding stage, but stage-specific shifts in these relationships are often not considered in studies of habitat use and survival. We investigated habitat use for nests and broods in the Mountain plover as an exemplar of a ground-nesting species with precocial, mobile young to explore site- and breeding stage-specific responses to vegetation structure, food availability, and predation risk. We located and monitored nests and broods at two study sites in Colorado occupied by geographically separated breeding populations of plovers. We quantified the three covariate categories across standardized site-wide grids in 2021 and 2022. We employed a resource selection analysis to evaluate 10 a priori working hypotheses for how environmental covariates may influence the habitat used by plovers for nesting and brood-rearing. Model comparison results suggest that habitat use relative to availability is best explained by a quadratic relationship with vegetation structure dependent on breeding stage and site but not influenced by food availability or predation risk. Specifically, probability of use for nest sites was highest in areas with shorter vegetation, consistent with previous research, while probability of use for broods was lowest in areas with moderate groundcover height and bare ground coverage and highest at the extremes. These results emphasize the importance of investigating stage-specific habitat use for species with precocial young.

Many animals communicate using sequences of signals, but identifying recurrent, non-random signal combinations remains methodologically challenging. Collocation analyses are increasingly popular approaches for detecting which signals animals combine at rates greater than expected by chance. However, existing methods for animal collocation analysis face several limitations that reduce their statistical rigour: they lack uncertainty estimates, fail to control for non-independence in sampled data, and do not account for inflated family-wise error rates when identifying attraction among many different signal types. These limitations restrict the broader applicability of animal collocation analysis, including preventing robust comparisons of signal combination strength between cohorts (e.g. populations, sexes or age classes). We adapt a novel form of Multiple Distinctive Collocation Analysis using Pearson residuals (MDCA-Pr) that addresses these statistical limitations, and validate its use in animal communication research in three ways: first, using numerous simulated datasets of different sizes and levels of signal recombination; second, using simulated data to evaluate the performance of MDCA-Pr in intercohort comparisons, and third, by demonstrating how MDCA-Pr can be applied to compare the vocal sequences produced by male and female captive-living common marmosets (Callithrix jacchus). MDCA-Pr shows high sensitivity, including at small sample sizes, and generally low false-positive rates, which we further reduce by applying additional criteria for identifying attraction between signals. During intercohort comparisons, MDCA-Pr is conservative, with low false-positive rates, and statistical power increases with sample size. MDCA-Pr is a robust method for evaluating signal attraction in animal communication and enables accurate intercohort comparison of animal signal combinations. Significance StatementBy assessing the performance of MDCA-Pr on simulated animal-like data, we demonstrate that this method reliably detects signal combinations within and across animal cohorts, while overcoming statistical limitations of previous collocation analyses. We present an analytical pipeline for applying MDCA-Pr to animal signal data, including for intercohort comparisons, enabling identification and comparison of combinatorial strategies across entire signal repertoires. We illustrate this approach by comparing call combination strategies of male and female common marmosets when presented with food under experimental conditions, finding similar combinatorial strategies between sexes. MDCA-Pr therefore permits rigorous characterization of animal signal combinatoriality and opens avenues for investigating how demographic, social, and group-level factors influence combinatorial patterns.

Parental care can shape post-fledging behaviour through provisioning, guidance and social information, yet its absence may alter how young birds establish space use and habitat preferences. We tested the consequences of absent parental care by comparing, hand-reared juvenile herring gulls released without parents with wild, parent-reared conspecifics, focusing on the first two months after fledging. Wild juveniles frequently revisited their natal nest during the first month, whereas hand-reared birds rarely returned to the release site; revisits declined in both groups by the second month but remained more common in wild birds. Wild juveniles used smaller ranges that subsequently expanded, while hand-reared birds began with larger ranges that later contracted, leading to convergence. Contrary to expectation, wild juveniles occurred in areas with higher human population density than hand-reared birds. Habitat use also differed between groups and changed over time. Early on, wild juveniles concentrated activity in anthropogenic and marine habitats, whereas hand-reared birds used rural green habitats more. Later, both groups shifted away from marine areas towards rural green habitats, reducing but not eliminating between-group differences. Short-term survival, did not differ between hand-reared and wild juveniles, indicating that parental care primarily reshaped early space use and habitat choice rather than immediate survival.

Corvids - members of the crow family - exhibit some of the most sophisticated cognitive abilities outside the primate lineage, yet the developmental origins of many of these abilities remain poorly understood. Here, we present a systematic review of the past 20 years (from 2005) of empirical research on corvid cognitive development, synthesising evidence across core/ foundational, social and physical cognitive domains. Using a structured search strategy and detailed coding framework, we identified 47 relevant studies spanning 16 corvid species. We evaluate and discuss developmental trajectories, species/ taxa-level variation and methodological robustness across studies. For within and between-taxa comparisons, we particularly focus on the best represented abilities in the coded sample: 1) object permanence and caching; 2) tool-use/ manufacture; 3) object manipulation and play; and 4) gaze following. Corvid developmental patterns show both parallels and divergences from those documented in primates and other taxa. However, the existing corvid evidence base is constrained by small samples, captive biases, limited longitudinal data and under-representation of key cognitive abilities, such as executive function, causal reasoning, self-control, metacognition, spatial memory and social learning. We outline critical gaps and future directions, emphasising the need for comparative, longitudinal and ecologically grounded approaches, including the science of magic and Theory of Mind, to better understand how early-life cognition shapes later behaviour, cognition and fitness in this model avian family.

In mammals, loud, high-pitched, and harsh-sounding calls typically accompany heightened emotional arousal, particularly during distress such as separation. However, whether subtle arousal reductions can be detected through acoustic analysis within a single negative context remains unclear. We investigated whether source-related acoustic parameters of puppy whines reflect arousal modulations induced by calming interventions during maternal separation. Thirty-five eight-week-old Beagle puppies were recorded under four conditions combining synthetic appeasing pheromone and a pressure harness. Vocal behavior, activity, whine duration, and intensity, did not significantly differ across treatments, suggesting interventions did not suppress separation-related vocal responses. Nevertheless, calming products selectively altered acoustic parameters known to index arousal in dog vocalizations. Puppies receiving combined treatments produced whines with lower fundamental frequency (fo) and reduced fo variability, while pheromone exposure increased call tonality, reflected by reduced jitter and shimmer and elevated harmonics-to-noise ratios. Spectral entropy remained unchanged, possibly because the proportion of whines containing nonlinear phenomena did not vary across conditions. Reductions in fo, fo variability, and acoustic roughness are consistent with established correlates of lower arousal in mammals, suggesting source-related vocal parameters sensitively capture subtle arousal shifts even when overt vocal behavior remains stable, supporting their use as bioacoustic indicators for evaluating welfare interventions.

The large-scale release of ring-necked pheasants, Phasianus colchicus, for recreational shooting in the UK raises concerns about ecological impacts, particularly on sensitive ecological sites. Current assumptions suggest dispersal is typically <500m from release pens, yet empirical evidence is limited. This study tracked 110 GPS-tagged pheasants from 11 woodland release pens across nine shooting estates, monitoring movements through pre-shooting, shooting and post-shooting phases. Most birds (73%) travelled a maximum distance beyond 500m during at least one of the three phases, with mean maximum distances of 863m, 1,493m and 1,307m per phase. During at least one phase, 26% of the 110 tagged birds spent most of their time (>50%) beyond 500m and 16% beyond 1,000m from their release pens. Early post-release movements were concentrated near pens, but ranging behaviour expanded during subsequent phases, with the percentages of birds spending >50% of their time beyond 500m and 1,000m, respectively: pre-shooting 6%, 2%; shooting 24%, 16%; post-shooting 13%, 9%. Accounting for mortality, the percentages of surviving birds spending >50% of their time beyond 500m and 1,000m increased: pre-shooting (n=110) 6%, 2%; shooting (n=71) 37%, 25%; post-shooting (n=27) 52%, 37%. Dispersal was greater with earlier release dates, higher pen and estate stocking densities and lower vegetative habitat quality in pens. Movements were directional rather than uniform, with most cohorts concentrating activity within a limited directional arc specific to the release site. Conservation site incursions occurred in 28 (25%) tagged birds, particularly where pens were closest to site boundaries; although 10 (36%) tagged birds encroached on conservation sites 872-2,319m from their release pen. These findings show that dispersal of released pheasants is further, more directed, and persistent than currently assumed.

Bird blowflies, Protocalliphora spp. (Diptera: Calliphoridae), are prevalent ectoparasites of altricial bird nestlings across the Holarctic region. Yet, their spatial and temporal dynamics of infestations, species composition, and interactions with parasitoids remain poorly understood. We present a 16-year (2004-2019) multisite study of bird blowfly infestations based on 2673 tree swallow, Tachycineta bicolor (Vieillot) (Passeriformes: Hirundinidae), nests collected across a 10 200-km{superscript 2} gradient of agricultural intensity in Quebec, Canada. Nest infestation prevalence and parasitic load varied markedly across space and time but showed synchronous recurrence at approximately 75% of sites, suggesting the influence of regional and local processes. Yearly rates of parasitoidism of bird blowfly puparia by Nasonia spp. wasps (Hymenoptera: Pteromalidae) were high but variable (48-90%), likely contributing to the temporal fluctuations in bird blowfly prevalence and load. Substantial interannual shifts in the relative abundance of Protocalliphora species (P. bennetti, P. metallica, and P. sialia) emphasised the importance of species-level identification in bird blowfly ecological studies. Large overlap in puparia size among species challenged the utility of traditional diagnostic traits for species identification. Finally, dormancy or mortality of Nasonia spp. occurred in 3-16% of Protocalliphora spp. puparia, depending on year. These findings highlight the importance of long-term, multitrophic, and spatially explicit monitoring to unravel the drivers of host-parasite-parasitoid dynamics.

Predation is a driving force in the ecology and evolution of prey, and primates exhibit diverse anti-predator strategies for minimizing risk. Because these behaviors can be costly, individuals must balance costs and benefits when responding to perceived threats. The cognitive capacity and behavioral plasticity of baboons make them an ideal taxon for studying the context-dependent variation in anti-predator strategies. Here, we used an autonomous, motion-activated playback experiment to study the behavioral responses of chacma baboons (Papio ursinus griseipes) to simulated predator encounters in Gorongosa National Park, Mozambique. We compared responses in 2021, when predator densities were relatively low, to responses in 2024, after predation increased due to lion (Panthera leo) population recovery and African wild dog (Lycaon pictus) reintroduction. We compared flight and vigilance responses to vocalizations of these common predators with responses to leopard (Panthera pardus), historically a key predator; spotted hyena (Crocuta crocuta), a rare predator; and cheetah (Acinonyx jubatus), absent historically and currently. We also assessed how responses varied with habitat, age-sex class, presence of offspring, and group size. Across 916 predator playbacks, baboons fled in 19% and displayed vigilance in 71% of trials. When predator density was higher, baboons displayed weakened antipredator responses, consistent with the risk allocation hypothesis. Baboons were more likely to flee in response to lion and wild dog cues. Juveniles fled more frequently than other demographic classes, while adult females with offspring were more vigilant. Overall, responses were highly heterogeneous, reflecting the substantial intraspecific variation and behavioral flexibility characteristic of baboons.

The Socotra Cormorant (Phalacrocorax nigrogularis) is a threatened seabird endemic to the coastal areas of the Arabian Gulf and the Arabian Sea, two regions separated by the Strait of Hormuz. Conserving threatened species requires clear delineation of population boundaries and the evaluation of genetic diversity. However, information on population structure and genetic variation, necessary for such an assessment, is lacking for the Socotra Cormorants. In this study, we assessed population structure and genetic diversity of Socotra Cormorants using two contrasting genetic markers: (1) maternally inherited mtDNA cytochrome oxidase 1 (COI) and (2) a nuclear non-coding region, {beta}-fibrinogen intron 7 (FIB7). A total of 279 individuals were sampled from four colonies in the Arabian Gulf and one colony on Hasikiyah Island in the Arabian Sea. Findings based on COI-variation suggest that the Arabian Gulf colonies represent one large population with extensive gene flow between Gulf colonies--except for the most distant pair of colonies--but isolated from Hasikiyah in the Arabian Sea. COI-variation indicated significant differentiation between the colonies inside the Gulf and the Hasikiyah colony. This is consistent with the reported distribution patterns, and may reflect phylogeographic processes of the region. The Gulf population showed substantially lower COI-diversity, with significantly lower nucleotide and haplotype diversity compared to Hasikiyah. In contrast, FIB7 results indicated extensive connectivity among colonies, with no detectable population structure or significant differences between the Gulf population and Hasikiyah. This study presents the first characterization of population structure and genetic diversity of Socotra Cormorants. The low genetic diversity coupled with relative isolation of the Gulf Socotra Cormorants raises conservation concerns regarding their long-term viability by potentially reducing fitness and eroding their evolutionary capacity to adapt to environmental change. LAY SUMMARYO_LIThe Socotra Cormorant is a threatened seabird found in the Arabian Gulf and Arabian Sea, but little was previously known about its population structure and genetic diversity. C_LIO_LIWe analyzed 279 birds from five nesting colonies (4 in the Gulf and 1 in the Arabian Sea), using two genetic markers to assess population connectivity and variation. C_LIO_LIWe found that the Socotra cormorants inside the Gulf appear to form a large, genetically isolated population with relatively low genetic diversity. C_LIO_LIThis is the first study that evaluates population structure and genetic diversity of this endangered seabird. C_LIO_LIThis is important information for the conservation of the Gulf Socotra cormorants because low genetic diversity, coupled with relative isolation, is associated with reduced fitness, and suggests that they may have a lower chance to adapt to environmental changes. C_LI

Helping-at-the-nest is often viewed as a precursor to reproduction, but switching between breeder and helper roles has been documented in some species. Such flexibility should depend on the opportunities and benefits of helping, which could differ between sexes due to dispersal strategies and social structure. However, whether breeding-helping flexibility is widespread and sex-specific remains unknown. Here, we investigated sex-specific strategies in breeding-helping flexibility using a 10-year dataset (1955 individuals) on sociable weavers (Philetairus socius), a colonial cooperative breeder in which males are typically philopatric whereas females disperse. Both sexes helped for several years, with males helping more frequently than females and for twice as long (0-13 vs 0-10 years). Around 40% of non-dispersing birds never became breeders and 50% of individuals bred without helping first. Both sexes switched roles between- and within-seasons but males were more likely to alternate (respectively four and six times more than females and up 15 switches across seven years). Our study reveals important flexibility and sex differences in breeder-helper roles, consistent with sex-biased dispersal, spatial breeding proximity and possible indirect fitness benefits. These factors could play a role promoting the evolution of helping across life-stages, not only pre-reproduction, but also reproductive and post-reproductive individuals.

Ringing-recoveries are an overarching element of population dynamic studies that allow estimating mortality causes and hence improve wildlife management. However, possible drawbacks of recovered rings reside in the fact that reporting probability is rarely known, but consistently lower than 100%. Thus, estimating harvest probabilities (mortality probability due to harvesting) of exploited species without knowledge of ring reporting probability by people exploiting these animals is not straightforward. We here provide the first ever reward-ring study carried out to evaluate European reporting probabilities, hence European harvest probabilities, in three species of ducks (Mallard Anas platyrhynchos, Eurasian Teal A. crecca and Common Pochard Aythya ferina). The 70 Euros reward on some rings was considered to yield a total return of the rings, allowing by comparison to evaluate the reporting probability of standard rings. After the initial year of ringing, annual reporting probability was very similar among the three species, at 0.63-0.66, suggesting two-thirds of the found rings are sent back to the ringing centre. This allowed computation of the annual harvest probability, which was up to 0.27 during the first months after ringing in fall but decreased to 0.04-0.10 during later years. Compared to North American results, the present estimates suggest birds are submitted to a heavy hunting mortality during the first months after ringing, but this pressure declines in later years, likely owing to counter selection of vulnerable/exposed individuals and/or learning by the birds.