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Increases in marine traffic represent a growing issue for marine wildlife, posing threats through the impacts of ship strikes and noise pollution. Baleen whales are especially vulnerable to these impacts, yet regional and species-specific information on exposure to such threats is lacking. This study uses AIS and observational data to provide the first assessment of baleen whale exposure to vessel traffic on the NW coast of Spain. Overlap with vessel traffic was detected for all areas where whales were sighted, indicating that these species may be at risk of vessel exposure and its associated impacts. Level of exposure to vessel traffic experienced by whales was species-specific, with risk of exposure appearing highest for minke whales. Vessel exposure also displayed intra- and inter-annual variability and a significant influence of feeding behaviour highlighting the need for dynamic management tools to minimise interactions between baleen whales and marine traffic off the Galician Coast.

Commercial forest plantations of fast-growing species have been established globally to meet increasing demands for timber, pulpwood, and other wood products. Industrial plantations may contribute to tropical forest conservation by reducing exploitation of primary and secondary natural forests. Whether such plantations can support critical elements of biodiversity, including provision of habitat and movement corridors for species of conservation concern, is an important question in Southeast Asia. Our objectives were to investigate relationships between habitat gradients and community attributes of medium-sized to large mammals in a mixed plantation mosaic in Bengkoka Peninsula, Sabah, East Malaysia. Data on mammals were collected using 59 remote camera stations deployed for a minimum of 21 days (24-hour sampling occasions) in three major land-use types: natural forest, Acacia plantations, and non-Acacia plantations (oil palm, rubber, young Eucalyptus pellita). We used sample-based rarefaction to evaluate variation in species richness with land use. We used generalized linear models and ordination analyses to evaluate whether variation in mammal detections and species composition was associated with habitat gradients. We recorded >22 mammal species over 1572 sampling occasions. Natural forest area was positively associated with mammal species richness and detections of threatened mammals. Overall detections of mammals increased with decreasing elevation, but decreased within, and close to, Acacia plantations. Detections of threatened mammals increased with greater proportions of natural forest and Acacia and increasing proximity to roads. Sample-based rarefaction indicated that species richness of mammals in Acacia and natural forest was considerably higher than observed. Both natural forest and Acacia plantations shared similar values for species richness and diversity, but non-Acacia plantations scored lower in both metrics. Mammal species composition differed among different types of land use. Smaller generalists used non-Acacia plantation forests. A variety of other mammals including some threatened species used natural forest, Acacia, or a combination of the two. Acacia plantations possess attributes supporting a diversity of mammal species, including those we defined as threatened based on IUCN criteria. However, this is likely a function of the habitat mosaic with natural forest in the study area and the mangrove forests on the fringes of the peninsula serving as refuges of mammal diversity. Retention and restoration of natural and mangrove forests may therefore enhance the conservation potential of industrial Acacia plantations. Additionally, controlled road access in conjunction with anti-poaching operations and strengthening public awareness are essential to reduce the threat of overexploitation.

Wildlife populations in southeast Asia are increasingly experiencing a broad array of anthropogenic threats, and mammalian carnivores are particularly vulnerable. Populations of the Malayan sun bear Helarctos malayanus are estimated to have declined by 30% over the last 30 years from forest conversion to industrial plantations and mortality associated with human–bear conflicts and illegal wildlife trade. However, the effects of industrial plantations on habitat selection and activity patterns of mammals that live at the protected area-plantation interface, including sun bears, are not well known. We investigated habitat selection and activity patterns of sun bears in Tabin Wildlife Reserve in Sabah, Malaysia. We deployed 83 remote camera sites to record sun bear detections during two sampling periods (2012–2013 and 2017). We used generalized linear models to examine relationships between sun bear presence and site covariates representing physical, environmental and anthropogenic elements of the landscape. Relative probability of sun bear presence was positively associated with distance to roads and elevation. Because most roads were on the reserve boundary and often associated with oil palm plantations, proximity to roads likely served as a surrogate measure of human accessibility and activity in peripheral areas of the reserve. Supporting that interpretation, sun bears close to the reserve boundary were primarily active at night, whereas daytime activity was more common for bears in the interior. Our findings indicate that sun bears alter behaviour and habitat selection likely in response to anthropogenic activities at the edges of Tabin Wildlife Reserve (112 200 ha). Because the ratio of edge to interior increases steeply with declining habitat area, smaller protected areas bordered by plantations are predicted to have greater impacts on sun bear behaviour and, potentially, population persistence. Effective conservation actions may benefit from management to improve the security of edge habitats for sun bears and other vulnerable species.

Many countries allow lawsuits to hold responsible parties liable for the environmental harm they cause. Such litigation remains largely untested in most biodiversity hotspots and is rarely used in response to leading drivers of biodiversity loss, including illegal wildlife trade. Yet, liability litigation is a potentially ground-breaking conservation strategy to remedy harm to biodiversity by seeking legal remedies such as species rehabilitation, public apologies, habitat conservation and education, with the goal of making the injured parties ‘whole’. However, precedent cases, expert guidance, and experience to build such conservation lawsuits is nascent in most countries. We propose a simplified framework for developing conservation lawsuits across countries and conservation contexts. We explain liability litigation in terms of three dimensions: (1) defining the harm that occurred, (2) identifying appropriate remedies to that harm, and (3) understanding what remedies the law and courts will allow. We illustrate the framework via a hypothetical lawsuit against an illegal orangutan trader in Indonesia. We highlight that conservationists’ expertise is essential to characterizing harm and identifying remedies, and could more actively contribute to strategic, science-based litigation. This would identify priority contexts, target defendants responsible for egregious harm, propose novel and meaningful remedies, and build new transdisciplinary collaborations. © 2021 The Authors. Conservation Letters published by Wiley Periodicals LLC

Traditional mark–recapture studies to estimate abundance and trends of Malayan sun bear (Helarctos malayanus) populations are impeded by logistics of live-trapping wild individuals. The development of noninvasive sampling techniques for monitoring sun bear populations is therefore crucial for targeted conservation action. Sun bears have short fur, and conventional hair-snagging devices are ineffective. Moreover, scats are rapidly decomposed by the warm, humid environment, as well as by invertebrates. In combination with camera-sampling, we tested 2 designs of hair traps (n = 45) in situ at Tabin Wildlife Reserve in Sabah, Malaysia, during April–October 2017, to obtain hair samples from wild sun bears. We also deployed 4 types of hair traps in rainforest enclosures with captive sun bears to evaluate hair-capture success and the effects of weathering, lure, and adhesive on polymerase chain reaction (PCR) amplification success. Wild adult male sun bears displayed back-rubbing behavior at hair traps and 6 individuals were identified based on unique chest marks. We collected 30 hair samples from wild sun bears, including 15 chest mark images of 6 individuals over 1,260 trap-nights. We detected adult males at hair traps more frequently than females and subadults. We obtained 39 hair samples in the captive trials. Extracted DNA from hair roots successfully amplified with mitochondrial (wild bears: 95%; captive bears: 97%) and microsatellite primers (wild bears: 100%; captive bears 87%). Adhesive and lure type did not affect PCR amplification, but weathering reduced amplification of microsatellite loci. This study is the first successful attempt to obtain genetic samples from wild sun bears using inexpensive, readily available materials such as duct tape, polybutyl glue, and locally sourced lures. The quality of genetic material from these genetic samples should be suitable for studies of population size and gene flow.

Inbreeding is often avoided in natural populations by passive processes such as sex-biased dispersal. But, in many social animals, opposite-sexed adult relatives are spatially clustered, generating a risk of incest and hence selection for active inbreeding avoidance. Here we show that in long-tailed tits (Aegithalos caudatus), a cooperative breeder that risks inbreeding by living alongside opposite-sex relatives, inbreeding carries fitness costs and is avoided by active kin discrimination during mate choice. First, we identified a positive association between heterozygosity and fitness, indicating that inbreeding is costly. We then compared relatedness within breeding pairs to that expected under multiple mate choice models, finding that pair relatedness is consistent with avoidance of first-order kin as partners. Finally, we show that the similarity of vocal cues offers a plausible mechanism for discrimination against first-order kin during mate choice. Long-tailed tits are known to discriminate between the calls of close kin and non-kin, and they favor first-order kin in cooperative contexts, so we conclude that long-tailed tits use the same kin discrimination rule to avoid inbreeding as they do to direct help towards kin.

1. Researchers studying mammals have frequently interpreted earlier or faster rates of ageing in males as resulting from polygyny and the associated higher costs of reproductive competition. 2. Yet few studies conducted on wild populations have compared sex-specific senescence trajectories outside of polygynous species, making it difficult to make generalised inferences on the role of reproductive competition in driving senescence, particularly when other differences between males and females might also contribute to sex-specific changes in performance across lifespan. 3. Here, we examine age-related variation in body mass, reproductive output and survival in dominant male and female meerkats, Suricata suricatta. Meerkats are socially monogamous cooperative breeders where a single dominant pair virtually monopolize reproduction in each group and subordinate group members help to rear offspring produced by breeders. 4. In contrast to many polygynous societies, we find that neither the onset nor the rate of senescence in body mass or reproductive output show clear differences between males and females. Both sexes also display similar patterns of age-related survival across lifespan, but unlike most wild vertebrates, survival senescence (increases in annual mortality with rising age) was absent in dominants of both sexes, and as a result, the fitness costs of senescence were entirely attributable to declines in reproductive output from mid- to late-life. 5. We suggest that the potential for intrasexual competition to increase rates of senescence in females – who are hormonally masculinised and frequently aggressive – is offset by their ability to maintain longer tenures of dominance than males, and that these processes combined lead to similar patterns of senescence in both sexes. 6. Our results stress the need to consider the form and intensity of sexual competition as well as other sex-specific features of life history when investigating the operation of senescence in wild populations.

Female song in birds is more widespread than previously thought but remains poorly studied. Relatively few researchers have compared the structure and function of female song with that of conspecific males, especially in non-duetting species. Here we investigate male and female song in the White-throated Dipper (Cinclus cinclus; hereafter ‘Dipper’), a highly territorial and largely monogamous passerine with a complex song in both sexes. The songs of individually marked birds were recorded over a 3-year period in order to compare the acoustic structure and production of song in males and females at different stages of the breeding cycle. No differences were found in the complexity, frequency or temporal characteristics of male and female songs. However, unpaired males recorded early in the breeding season sang more complex songs than males that were paired up and nest-building or whose breeding attempts were underway, suggesting that male song is used for mate attraction. By contrast, females sang most often during aggressive encounters with birds from outside their territory. Furthermore, males sang throughout the breeding season, when they are highly territorial, whereas females rarely sang after laying had begun. Together, these results support findings from other species that song structure varies with context and suggest that female song in Dippers may be used primarily in mate or territory defence.

Capsule: Pairs of White-throated Dippers Cinclus cinclus which defended winter territories bred earlier than non-territorial individuals, but there was no difference in reproductive success. Aims: The effect of winter territoriality on breeding ecology has rarely been studied in resident birds. We carried out a preliminary investigation of whether winter territorial behaviour and territory size affect the timing of reproduction, breeding territory size and reproductive success in a riverine bird, the White-throated Dipper. Methods: We monitored an individually marked population of White-throated Dippers in the UK. Wintering individuals were classified as either territorial or ‘floaters’ according to their patterns of occurrence and behaviour, and their nesting attempts were closely monitored in the subsequent months. Winter and breeding territory sizes were measured by gently ‘pushing’ birds along the river and recording the point at which they turned back. Results: All birds defending winter territories did so in pairs, but some individuals changed partners before breeding. Territorial pairs that were together throughout the study laid eggs significantly earlier than pairs containing floaters and those comprising territorial birds that changed partners. However, there were no significant differences in clutch size, nestling mass or the number of chicks fledged. There was no relationship between winter territory length and lay date or any measure of reproductive success, although sample sizes were small. Winter territories were found to be significantly shorter than breeding territories. Conclusion: Winter territoriality may be advantageous because breeding earlier increases the likelihood that pairs will raise a second brood, but further study is needed. Territories are shorter in winter as altitudinal migrants from upland streams increase population density on rivers, but this may also reflect seasonal changes in nutritional and energetic demands.

Capsule: Male White-throated Dippers Cinclus cinclus are more likely and quicker to respond to the playback of song than females, but both sexes are more likely to respond before the onset of breeding than after. Aims: Territoriality and the function of song in female birds have rarely been studied outside of the tropics or Australasia. We investigated territoriality and song function in males and females of a Northern temperate species, the White-throated Dipper. Methods: We conducted playback trials on established pairs and compared the responses of males and females according to the sex of the simulated intruder and the timing of playback relative to the onset of breeding. A response was classified as movement towards the speaker, singing or both. Results: Males were significantly more likely and quicker to respond to playback than females, but neither sex responded differently to the playback of male and female song. Both sexes were more likely to respond to playback before breeding had begun than after. Conclusions: Our results suggest that both males and females are territorial but that males take the dominant role in defence. Female song appears to elicit a similar response to male song and may play a role in territoriality or mate defence. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Capsule: Carbon dioxide (CO2) concentrations in the burrows of Sand Martins Riparia riparia increase with depth but have no detectable impact on fledging success.Aims: To investigate whether burrow depth and CO2 concentrations influence reproductive success in Sand Martins.Methods: We monitored two Sand Martin colonies along the River Lune, Lancashire, UK, to investigate the effect of burrow depth on reproductive success. We also measured CO2 levels in a sample of burrows to test whether burrow depth predicts CO2 concentration, and to test for a relationship between CO2 concentration and breeding success.Results: Burrow depth was significantly correlated with fledging success, but the correlation was positive in first broods and negative in second broods. The highest CO2 concentration recorded was 73 650 ppm and the mean concentration across burrows was 31 757 ppm. However, while CO2 concentrations were positively correlated with burrow depth after controlling for the number and age of nestlings, ...

Extreme weather events such as tropical cyclones are becoming more frequent, but efforts to understand their impact on wildlife have focused on population-level change rather than the behavioural responses of individuals. In this study, we monitored individually marked Brown Dippers Cinclus pallasii in upland Taiwanese streams in order to investigate the movements of these birds following typhoons in 2004, 2012 and 2013. Individuals moved significantly longer distances immediately after floods compared with before, and in typhoon years compared with other years. Most of these movements involved temporary displacement from a major stream to one of its tributaries, where population size and food abundance are typically lower. These results suggest that movements after flooding were not driven by food abundance but that relatively poor quality streams may provide an important refuge for birds following typhoons.

Mammalian carnivores play a vital role in ecosystem functioning. However, they are prone to extinction because of low population densities and growth rates, and high levels of persecution or exploitation. In tropical biodiversity hotspots such as Peninsular Malaysia, rapid conversion of natural habitats threatens the persistence of this vulnerable group of animals. Here, we carried out the first comprehensive literature review on 31 carnivore species reported to occur in Peninsular Malaysia and updated their probable distribution. We georeferenced 375 observations of 28 species of carnivore from 89 unique geographic locations using records spanning 1948 to 2014. Using the Getis-Ord Gi*statistic and weighted survey records by IUCN Red List status, we identified hotspots of species that were of conservation concern and built regression models to identify environmental and anthropogenic landscape factors associated with Getis-Ord Gi* z scores. Our analyses identified two carnivore hotspots that were spatially concordant with two of the peninsula's largest and most contiguous forest complexes, associated with Taman Negara National Park and Royal Belum State Park. A cold spot overlapped with the southwestern region of the Peninsula, reflecting the disappearance of carnivores with higher conservation rankings from increasingly fragmented natural habitats. Getis-Ord Gi* z scores were negatively associated with elevation, and positively associated with the proportion of natural land cover and distance from the capital city. Malaysia contains some of the world's most diverse carnivore assemblages, but recent rates of forest loss are some of the highest in the world. Reducing poaching and maintaining large, contiguous tracts of lowland forests will be crucial, not only for the persistence of threatened carnivores, but for many mammalian species in general.

In animal societies, characteristic demographic and dispersal patterns may lead to genetic structuring of populations, generating the potential for kin selection to operate. However, even in genetically structured populations, social interactions may still require kin discrimination for cooperative behaviour to be directed towards relatives. Here, we use molecular genetics and long‐term field data to investigate genetic structure in an adult population of long‐tailed tits Aegithalos caudatus, a cooperative breeder in which helping occurs within extended kin networks, and relate this to patterns of helping with respect to kinship. Spatial autocorrelation analyses reveal fine‐scale genetic structure within our population, such that related adults of either sex are spatially clustered following natal dispersal, with relatedness among nearby males higher than that among nearby females, as predicted by observations of male‐biased philopatry. This kin structure creates opportunities for failed breeders to gain indirect fitness benefits via redirected helping, but crucially, most close neighbours of failed breeders are unrelated and help is directed towards relatives more often than expected by indiscriminate helping. These findings are consistent with the effective kin discrimination mechanism known to exist in long‐tailed tits, and support models identifying kin selection as the driver of cooperation.

Kin selection has played an important role in the evolution and maintenance of cooperative breeding behaviour in many bird species. However, although relatedness has been shown to affect the investment decisions of helpers in such systems, less is known about the role that kin discrimination plays in other contexts, such as communal roosting. Individuals that roost communally benefit from reduced overnight heat loss, but the exact benefit derived depends on an individual's position in the roost which in turn is likely to be influenced by its position in its flock's dominance hierarchy. We studied the effects of kinship and other factors (sex, age, body size and flock sex ratio) on an individual's roosting position and dominance status in captive flocks of cooperatively breeding long-tailed tits Aegithalos caudatus. We found that overall, kinship had little influence on either variable tested; kinship had no effect on a bird's position in its flock's dominance hierarchy and the effect of kinship on roosting position was dependent on the bird's size. Males were generally dominant over females and birds were more likely to occupy preferred roosting positions if they were male, old and of high status. In this context, the effect of kinship on social interactions appears to be less important than the effects of other factors, possibly due to the complex kin structure of winter flocks compared to breeding groups.

Rates of extra-pair paternity (EPP) have frequently been associated with genetic relatedness between social mates in socially monogamous birds. However, evidence is limited in mammals. Here, we investigate whether dominant females use divorce or extra-pair paternity as a strategy to avoid the negative effects of inbreeding when paired with a related male in meerkats Suricata suricatta, a species where inbreeding depression is evident for several traits. We show that dominant breeding pairs seldom divorce, but that rates of EPP are associated with genetic similarity between mates. Although extra-pair males are no more distantly related to the female than social males, they are more heterozygous. Nevertheless, extra-pair pups are not more heterozygous than within-pair pups. Whether females benefit from EPP in terms of increased fitness of the offspring, such as enhanced survival or growth, requires further investigations.

Maternal investment in offspring development is a major determinant of the survival and future reproductive success of both the mother and her young. Mothers might therefore be expected to adjust their investment according to ecological conditions in order to maximise their lifetime fitness. In cooperatively breeding species, where helpers assist breeders with offspring care, the size of the group may also influence maternal investment strategies because the costs of reproduction are shared between breeders and helpers. Here, we use longitudinal records of body mass and life history traits from a wild population of meerkats (Suricata suricatta) to explore the pattern of growth in pregnant females and investigate how the rate of growth varies with characteristics of the litter, environmental conditions, maternal traits and group size. Gestational growth was slight during the first half of pregnancy but was marked and linear from the midpoint of gestation until birth. The rate of gestational growth in the second half of pregnancy increased with litter size, maternal age and body mass, and was higher for litters conceived during the peak of the breeding season when it is hot and wet. Gestational growth rate was lower in larger groups, especially when litter size was small. These results suggest that there are ecological and physiological constraints on gestational growth in meerkats, and that females may also be able to strategically adjust their prenatal investment in offspring according to the likely fitness costs and benefits of a particular breeding attempt. Mothers in larger groups may benefit from reducing their investment because having more helpers might allow them to lower reproductive costs without decreasing breeding success.

How individuals colonising novel environments overcome the diverse suite of new selection pressures is a fundamental question in ecology and evolution. Urban environments differ markedly from the rural ones that they replace and successful colonisation of urban areas may therefore require local adaptation and phenotypic/genetic divergence from ancestral populations. Such a process would be facilitated by limited dispersal to and from the novel habitat. Here we assess divergence in migratory behaviour between seven pairs of urban and rural European blackbird Turdus merula populations along a 2800 km transect across Europe. This former forest specialist is now amongst the most abundant urban birds across most of its range. We use a stable isotope approach due to the lack of sufficient ringing data from multiple urban populations, and compare hydrogen isotopic ratios of tissues grown in the breeding (feathers) and wintering areas (claws) to derive an index of long distance migratory behaviour. We find a tendency for urban blackbirds to be more sedentary than rural ones at all sites and this divergence is particularly strong at the north-eastern limit of our transect, i.e. in Estonia and Latvia. These urban populations are those that have been established most recently (from the late 1930s to 1950s) implying that urbanisation can promote rapid ecological divergence. The increased sedentary behaviour of urban birds could promote further ecological divergence between rural and urban populations, such as the earlier breeding of urban blackbirds, and in some cases may contribute to their previously documented genetic divergence.

In animal societies, kin selection is a critical evolutionary process, with cooperation evolving principally among relatives living in kin-structured populations. Theoretical and empirical studies have largely focused on population viscosity--the timing or distance of dispersal--as the key factor generating kin structure. This is despite extensive theoretical broadening of the factors and processes influencing effective population size, variance in reproduction, and relatedness. Here, we explore predation mortality as a specific driver of population-level reproductive skew and variance in fecundity to show how a common and perhaps underappreciated event in organism life history can give rise to patterns of relatedness. We develop our case study around an empirically derived model where elevated relatedness arises from predation that alters the timing and nature of offspring mortality, essentially driving variance in fecundity. This leads to dramatic changes in the emergent kin structure of the surviving breeding population. Our in-silico experiments recover the theoretical predictions that when predation acts on clusters of individuals and effectively removes whole family groups (i.e., broods), rather than individuals, from the pool of potential recruits, there is a greater kin structure in the emergent adult population. We conclude that empirical attempts to understand the factors promoting kin-structured populations and the evolution of sociality should now match theoretical efforts to be more inclusive of ecological process generating life history and demographic variability. Copyright 2011, Oxford University Press.

Competition between females is particularly intense in cooperatively breeding mammals, where one female monopolises reproduction in each group. Chronic competition often affects stress and may therefore have long-term consequences for fitness, but no studies have yet investigated whether intrasexual competition has effects of this kind and, in particular, whether it affects rates of reproductive senescence. Here, we use long-term data from a wild population of meerkats to test whether reproductive success and senescence in dominant females are affected by the degree of intrasexual competition experienced prior to dominance acquisition. Females that experienced greater competition had lower breeding success and higher rates of reproductive senescence. Furthermore, females that were evicted from the group more frequently as subordinates had lower breeding success when dominant. We conclude that the intense intrasexual competition between females in cooperatively breeding groups may carry fitness costs over a longer period than is usually recognised.

Cooperative breeding has evolved primarily in species in which individuals are organized into family groups, and kin selection is considered to be a major force in the evolution of helping behaviour. Family groups are generally thought to form through delayed or limited dispersal, but dispersal patterns vary considerably both between species and in different populations of the same species, and the relationship between dispersal, kinship and cooperation is poorly understood. In this study, we combined long-term observational and genetic data to compare the patterns of demography, kinship and helping in two populations of long-tailed tits, Aegithalos caudatus, a species that exhibits kin-biased helping by failed breeders but not delayed dispersal. Both populations had the same annual breeding success, but philopatric recruitment rates were significantly higher in one population, especially for females. This led to a correspondingly higher proportion of individuals having at least one close relative in that population. Surprisingly, however, there was no difference in the pattern of helping behaviour between the two populations in terms of helper prevalence, helper sex or the relatedness between helpers and the breeders they assisted. We discuss possible explanations and highlight the limitations of population-level analyses for understanding the relationship between demography and cooperation.

In most cooperatively breeding vertebrates, dominant breeders have higher reproductive success and live longer than subordinate helpers, and subordinates might consequently be expected to challenge the dominants in their group for status. However, in contrast to noncooperative species, challenges for dominance are rare. This could be because subordinates are unable to displace dominants or because the risk of attempting to do so is prohibitively high. Alternatively, because subordinates are commonly the offspring of dominants and more established breeders tend to produce more young, subordinates may maximize their inclusive fitness by allowing related dominants to maintain their position and helping them to raise future offspring. Here, we use more than 13 years of data from a wild population of Kalahari meerkats Suricata suricatta to investigate whether subordinate females would be likely to gain higher inclusive fitness by displacing their dominant mothers than by remaining as helpers. We first show that the breeding success of dominant females increases during the first 2‐3 years of their tenure and then declines. Combining estimates of breeding success in each year of tenure with age-specific survival probabilities, we then calculate the reproductive value of successful challengers and nonchallengers. Our results show that, in any year, subordinate females would achieve higher inclusive fitness by displacing their dominant mother than by remaining as helpers. We conclude that the low frequency with which displacement occurs probably reflects the potential costs associated with challenging for status and the low probability of success. Key words: cooperative breeding, dominance, meerkat, reproductive success, reproductive value, social dynamics. [Behav Ecol]

Song complexity and singing frequency in male birds are shaped by female choice; they signal male quality because song is costly to develop and produce. The timing of song learning and the development of the brain structures involved occur during a period when chicks are exposed to a number of potential stressors. The quality and quantity of song produced by adults may therefore reflect the level of stress experienced during early life, a theory known as the ‘developmental stress hypothesis’. We tested this hypothesis using song recordings and life-history data from an individually marked, long-term study population of wild dippers (Cinclus cinclus). The extent to which early life conditions predict adult song traits was investigated using natal brood size as a measure of sibling competition; the rate of provisioning by parents as a proxy for nutritional stress; and residuals of the linear regression between body mass and tarsus length as a measure of nestling condition. The syllable diversity in the songs of adult males was positively correlated with their body condition as nestlings, but there was no significant correlation with either provisioning rate or brood size. Provisioning rate did, however, predict song rate; males in relatively poor condition as nestlings or those raised in smaller broods which were fed more frequently by their parents sang at a higher rate in adulthood. These results support the developmental stress hypothesis and provide some of the first evidence from a wild bird of how the conditions experienced during early life impact adult song. Song traits may therefore provide females with information regarding both the current condition and developmental history of males.

In 1988 a ringing study was commenced with the aim of determining patterns of dispersal from a large heronry in Greater Manchester, north‐west England. Between 1988 and 2008, over 900 nestling Grey Herons Ardea cinerea were ringed at the heronry, rings from 53 of which were subsequently recovered. The overall annual recovery rate was 5.7% but this declined significantly from 7.5% between 1988 and 1996 to 3.8% between 1997 and 2007. Around 60% of ring recoveries were within the first year of the bird's life. There was a statistically significant bias in dispersal direction towards the north‐east, with a number of birds being reported in midwinter up to 100 km to the north‐east. This predominantly northeastward dispersal may have been associated with a range extension in that direction, facilitated by a succession of milder winters.

Despite increasing interest in urban ecology most attention has focussed on describing changes in assemblage composition and structure along urbanisation gradients, whilst relatively little research has focussed on the mechanisms behind these changes. Ecological theory predicts that alterations in biotic interactions are particularly likely to arise, especially with regard to disease risk. Here, we report on differences in prevalence of avian malaria and tick infection and intensity in 11 paired urban and rural blackbird Turdus merula populations from across the western Palearctic. We find large and consistent reductions in tick prevalence and intensity in urban areas. There are also large reductions in the prevalence of avian malaria in many, but not all, urban areas. The proportion of first year birds in urban populations is significantly lower than that in rural ones, and across the more natural rural sites southerly populations contain fewer first years than northern ones. These patterns are expected to arise if survival rates are higher in urban areas, and are negatively correlated with latitude.

1. Communal roosting behaviour in birds is hypothesized to reduce the risk of starvation by lowering the energetic expenditure required to survive the night. However, the metabolic benefit gained is likely to depend on various factors, including an individual's position within the roost. 2. The long-tailed tit Aegithalos caudatus L. is a social species that lives in flocks during the non-breeding season, forming linear roosting huddles in which individuals compete to avoid occupying the peripheral positions at either end of the roost. Using observations of 18 temporarily captive flocks of long-tailed tits, we examine the effects of position and other factors on the mass lost during roosting. 3. We found that, on average, long-tailed tits lost about 9% of their body mass overnight, and that individuals occupying the peripheral positions in a roost lost significantly more mass than those occupying inner positions. 4. Overnight mass loss was related to minimum temperature, being greatest at 4 degrees C and decreasing at higher and lower temperatures. This result suggests that long-tailed tits may use facultative nocturnal hypothermia to reduce energetic costs at low ambient temperature. Mass loss also tended to increase with group size, perhaps because of the greater competition for inner positions in larger flocks, although we have no direct evidence for this. Mass loss was also positively correlated with mass when going to roost, and males lost marginally more mass than females. 5. There was no evidence that individuals strategically adjusted their daily mass when going to roost in relation to their likely roosting position even though outer positions are consistently and therefore predictably occupied by the same individuals on successive nights. 6. We conclude that long-tailed tits mitigate the costs of surviving the night by roosting communally, but the benefits gained vary in relation to position within the roost, explaining previous observations of competitive interactions during roost formation. 7. The benefit derived from communal behaviour is likely to vary among individuals and the degree of conflict over these benefits is likely to depend on both intrinsic and extrinsic factors.

Urban areas occupy a large and growing proportion of the earth. Such sites exhibit distinctive characteristics relative to adjacent rural habitats, and many species have colonised and now successfully exploit urban habitats. The change in selection pressures as a result of urbanisation has led to trait divergence in some urban populations relative to their rural counterparts, but studies have generally been local in scale and the generality of differentiation thus remains unknown. The European blackbird Turdus merula is one of the commonest urban bird species in the Western Palearctic, but populations vary substantially in the length of time they have been urbanised. Here we investigate patterns of morphological variation in European blackbirds occupying 11 paired urban and rural habitats across much of the urbanised range of this species and spanning 25 degrees of latitude. First, we assessed the extent to which urban and rural blackbirds are differentiated morphologically and the consistency of any differentiation across the range. Paired urban and rural Blackbird populations frequently exhibited significant morphological differences, but the magnitude and direction of differentiation was site dependent. We then investigated whether the nature of latitudinal gradients in body-size differed between urban and rural populations, as predicted by differences in the climatic regimes of urban and rural areas. Blackbird body-size exhibited strong latitudinal gradients, but their form did not differ significantly between urban and rural habitats. The latitudinal gradient in body size may be a consequence of Seebohm's rule, that more migratory populations occurring at high latitudes have longer wings. We conclude that while there can be substantial morphological variation between adjacent urban and rural bird populations, such differentiation may not apply across a species' range. Locality specific differentiation of urban and rural blackbirds may arise if the selection pressures acting on blackbird morphology vary in an inconsistent manner between urban and rural habitats. Alternatively, phenotypic divergence could arise in a stochastic manner depending on the morphological traits of colonists, through founder effects.

Birds are an ideal model system for studying many aspects of animal behaviour. Throughout the last 100 years, ringing has been an essential tool in avian behavioural research as it allows birds to be identified and observed on an individual basis. Here, I introduce some of the most important and active research areas, including the study of dispersal, feeding behaviour, mating systems, sociality and vocal communication. This review highlights the pivotal role that ringing will continue to play in developing our knowledge and understanding of animal behaviour and the importance of an organised ringing scheme combining the efforts of volunteer ringers and scientists.

Dispersal is a fundamental but poorly understood process in ecology, evolution and conservation. Natal dispersal patterns are a major determinant of population kin structure and thus may play a key role in social evolution. We studied natal dispersal in the cooperatively breeding long-tailed tit Aegithalos caudatus, a non-territorial species that does not exhibit delayed dispersal. We investigated the factors associated with local recruitment and dispersal distance using 11 years of data, and generated dispersal distance distributions (DDDs) before and after correcting for sampling bias. We also examined how dispersal direction varied between and within nests, using a novel randomisation method to correct for bias. Recruitment was male-biased and increased with nestling weight, and there were significant nest and year effects. Neither sex nor weight had a significant effect on dispersal distance, but distance increased with brood size and there was a significant nest effect. The observed DDD was right-skewed but the corrected DDD was almost symmetrical, and this correction more than doubled estimates of mean dispersal distance and fledgling recruitment rate. There was no tendency across nests for birds to disperse in a particular direction, but siblings dispersed in similar directions. These results provide a detailed description of natal dispersal in long-tailed tits with minimal bias. They also demonstrate the importance of studying the different aspects of dispersal in combination, and show that direction is an important component of dispersal that is usually overlooked. The pattern of natal dispersal is consistent with the nature of helping behaviour in long-tailed tits, and may play an important role in the evolution and maintenance of cooperation despite the absence of delayed dispersal. © 2008 The Authors.

Communal roosting is widespread among social animals and has several hypothesized functions, including reduction of predation risk and thermoregulatory costs, and information sharing. The benefit derived from roosting in close proximity to conspecifics is likely to depend on an individual's position within the roost, but there have been few quantitative studies of the process of communal roost formation and the factors influencing relative positions. We studied the communal roosting behaviour of temporarily captive flocks of long-tailed tits, Aegithalos caudatus, a cooperative breeder that forms flocks during the nonbreeding season. Our objectives were to determine whether (1) individuals compete for particular positions within roosts, (2) individuals achieve consistent positions within roosts, and (3) an individual's roost position is a function of its dominance status. During roost formation birds were more likely to move to inner positions regardless of whether they started in an outer or inner position. However, as the number of birds in the roost increased during roost formation, birds in outer positions were less likely to relocate to an inner position. The same individuals occupied outer positions in a roost on successive nights, but there was no consistency in the occupation of specific inner positions. Birds occupying outer roost positions were significantly less dominant than those occupying inner positions. Our results show that long-tailed tits compete for inner positions within communal roosts, and that an individual's dominance status within a flock influences the outcome of this competition. (c) 2006 The Association for the Study of Animal Behaviour, Published by Elsevier Ltd. All rights reserved.

Contact calls are ubiquitous among birds and are important in mediating social interactions. Despite this, the structure and function of these vocalizations have received relatively little attention, and the ontogeny of all bird calls is poorly known. In co-operatively breeding Long-tailed Tits Aegithalos caudatus, helpers preferentially provide care at the nests of close relatives and contact calls act as cues for kin recognition. However, it is not known whether these calls act as individual-specific or family-specific cues, or if they differ between the sexes. Furthermore, the precise nature and timing of the development of these calls is not known. Here we use spectrographic cross-correlation to show that two different contact calls in the Long-tailed Tit exhibit some degree of family-specificity but no sex-specificity, and the implications for kin recognition are discussed. We also provide evidence that both call types develop in the nest, and we give one of the first descriptions of nestling vocalizations from hatching through to fledging in a passerine species.

In many cooperatively breeding birds, kin selection has an important role in the evolution and maintenance of social behaviour, and 'helpers' can maximize indirect fitness gains by preferentially allocating care to close relatives. Although there is evidence for kin-biased helping behaviour in several species, the mechanism of kin recognition underlying this behaviour is poorly understood. Vocalizations are the most commonly used cues in avian recognition systems, but the effectiveness of vocal signals as reliable recognition cues must depend on how they are acquired. However, there have been no experimental studies of the development of vocal recognition cues in cooperative birds; indeed, the ontogeny of all bird vocalizations other than song is poorly known in any species. Here, we show that cooperatively breeding long-tailed tits (Aegithalos caudatus) can discriminate between kin and non-kin according to the individual-specific characteristics of contact calls, and show experimentally that individuals learn these calls from provisioning adults during the nestling period. Finally, we show that the pattern of cooperative behaviour in this species is consistent with the use of recognition cues learned through association.

The ability to discriminate between individuals or groups of individuals is important for the evolution of sociality. Individual vocal recognition is thought to be widespread in social birds, yet few studies have investigated its role in cooperatively breeding species. In long-tailed tits, helpers preferentially provide care to close kin, and individuals are able to discriminate between the vocalisations of kin and non-kin. However, the mechanism underlying this recognition system is unknown. Here we quantify the relative variation between and within individuals in three of the contact calls used by this species. Spectrographic cross-correlation revealed that two of these calls, the 'churr' and the 'triple', were individually distinct. We therefore analysed the variation in a series of acoustic parameters in each of these two vocalisations. For both the churr and the triple, discriminant function analysis was able to allocate calls to the correct individuals according to variation in several frequency parameters. We hypothesise that long-tailed tits are able to discriminate between the calls of conspecifics based on these parameters. This is the first quantitative description of potential recognition cues in a cooperatively breeding bird in which vocal discrimination is known to occur.

1. The aim of this study was to investigate the structure and thermoregulatory function of nests of the Long-Tailed Tit, Aegithalos caudatus. 2. The feather lining of Long-Tailed Tit nests represents a major portion (41%) of the total nest mass. 3. The mass of feathers varied among nests and declined through the breeding season, but there was no seasonal loss of nest insulation quality because of increasing ambient temperatures. 4. In an experiment to investigate the seasonal decline in the feather mass of nests, feathers were added to nests at an early stage of the lining phase of nest construction. Nest structure and insulating properties were then examined following nest completion. 5. The total mass of feathers in treatment and control nests did not differ significantly and there was no significant difference in their nest insulation quality. 6. Our results demonstrate that Long-Tailed Tits adjust their nest-building behaviour according to the nest's thermal environment. Moreover, nest structure appears to be adjusted to prevailing environmental conditions rather than being a function of feather availability or time constraints.

Helping behaviour in cooperative breeding systems has been attributed to kin selection, but the relative roles of direct and indirect fitness benefits in the evolution of such systems remain a matter of debate. In theory, helpers could maximize the indirect fitness benefits of cooperation by investing more in broods with whom they are more closely related, but there is little evidence for such fine-scale adjustment in helper effort among cooperative vertebrates. In this study, we used the unusual cooperative breeding system of the long-tailed tit Aegithalos caudatus to test the hypothesis that the provisioning effort of helpers was positively correlated with their kinship to broods. We first use pedigrees and microsatellite genotypes to characterize the relatedness between helpers and breeders from a 14 year field study. We used both pedigree and genetic approaches because long-tailed tits have access to pedigree information acquired through social relationships, but any fitness consequences will be determined by genetic relatedness. We then show using both pedigrees and genetic relatedness estimates that alloparental investment by helpers increases as their relatedness to the recipients of their care increases. We conclude that kin selection has played a critical role in moulding the investment decisions of helpers in this cooperatively breeding species.

1. Senescence (or 'ageing') is a widespread and important process in wild animal populations, but variation in ageing patterns within and between species is poorly understood. 2. In cooperatively breeding species, the costs of reproduction are shared between breeders and one or more helpers. The effects of ageing in breeders may therefore be moderated by the presence of helpers, but there have been very few studies of senescence patterns in natural populations of cooperative breeders. 3. Here, we use 13 years of data from a long-term study population of wild meerkats (Suricata suricatta) to investigate age-related changes in several traits known to be key components of reproductive success in females of this species. 4. Four of the six traits studied exhibited significant declines with age, indicating senescence. Litter size, the number of litters produced per year and the number of pups that survived to emergence from the natal burrow per year all increased with female age up to a peak at c. 4 years, and declined steeply thereafter; the mean pup weight at emergence in a given litter declined steadily from age zero. 5. These results provide the first evidence of reproductive senescence in a wild population of a cooperatively breeding vertebrate. Breeding success declined with age despite the sharing of reproductive costs in this species, but further study is needed to investigate whether helping affects other aspects of senescence, including survival.

Urban areas are expanding rapidly, but a few native species have successfully colonized them. The processes underlying such colonization events are poorly understood. Using the blackbirdTurdus merula, a former forest specialist that is now one of the most common urban birds in its range, we provide the first assessment of two contrasting urban colonization models. First, that urbanization occurred independently. Second, that following initial urbanization, urban-adapted individuals colonized other urban areas in a leapfrog manner. Previous analyses of spatial patterns in the timing of blackbird urbanization, and experimental introductions of urban and rural blackbirds to uncolonized cities, suggest that the leapfrog model is likely to apply. We found that, across the western Palaearctic, urban blackbird populations contain less genetic diversity than rural ones, urban populations are more strongly differentiated from each other than from rural populations and assignment tests support a rural source population for most urban individuals. In combination, these results provide much stronger support for the independent urbanization model than the leapfrog one. If the former model predominates, colonization of multiple urban centres will be particularly difficult when urbanization requires genetic adaptations, having implications for urban species diversity.

Kin selection is a major force in social evolution, but dispersal is often assumed to reduce its impact by diluting kinship. In most cooperatively breeding vertebrates, in which more than two individuals care for young, juveniles delay dispersal and become helpers in family groups. In long-tailed tits ( Aegithalos caudatus ), however, offspring disperse to breed and helpers are failed breeders that preferentially aid kin. Helping also occurs among immigrants, but their origins are unknown and cooperation in these cases is poorly understood. Here, we combine long-term demographic and genetic data from our study population to investigate immigration and helping in this species. We first used a novel application of parentage analysis to discriminate between immigrants and unknown philopatric recruits. We then cross-checked sibship reconstruction with pairwise relatedness estimates to show that immigrants disperse in sibling coalitions and helping among them is kin biased. These results indicate that dispersal need not preclude sociality, and dispersal of kin coalitions may help maintain kin-selected cooperation in the absence of delayed dispersal.

This chapter describes some aspects of research on the cooperative breeding system of the long tailed tit Aegithalos caudatus. The principal aim of the chapter is to bring together evidence from various sources concerning the role of kin selection and ecological constraints in the evolution of cooperative breeding in this species. Many studies of vertebrate cooperative breeding systems have shown that helpers assist relatives in raising their offspring. A major reason for initiating a study on long tailed tits is that their helping behavior is atypical and does not conform to this sequence of events because all helpers are failed breeders that ‘‘redirect’’ their care to become helpers. The ability to discriminate between kin and non kin plays a major role in the evolution of social behavior. The direct fitness benefits of helping are those that enhance the personal reproductive success of helpers. The direct fitness benefits of helping are those that enhance the personal reproductive success of helpers. Helpers may gain indirect fitness benefits either by helping relatives to increase productivity of their current breeding attempt, or by reducing the reproductive costs of related breeders, thereby enhancing their survival. The main conclusions regarding the role of kin selection in the evolution of cooperative breeding in long tailed tits are have been listed out: (1) helpers exhibit a kin preference in helping behavior using a learned vocal kin recognition mechanism, (2) helpers increase the productivity of their relatives by increasing recruitment of fledglings of the helped brood, and (3) the kin selected fitness benefit of helping is the sole source of inclusive fitness for a substantial proportion of individuals.