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Rising temperatures and anthropogenic noise are two of the most pervasive and well researched anthropogenic stressors affecting avian species globally. Despite often triggering similar behavioural responses in birds, and frequently co‐occurring (particularly in urban areas), the impact of these stressors are primarily investigated in isolation. Here, we discuss and compare the most commonly researched effects of anthropogenic noise and rising temperatures on avian behaviour. We then outline recent findings on the impacts of these two stressors on cognition in birds, which underpins many behavioural adjustments. We find that both anthropogenic noise and high temperatures, when investigated in isolation, impact avian behaviours such as foraging, the antipredator response, and interactions with conspecifics. We also find that both these stressors can lead to cognitive impairment, but the occurrence and magnitude of impairment varies depending on the cognitive trait examined. Finally, we discuss the limited studies that have investigated these two anthropogenic stressors simultaneously and outline different scenarios in which additive, synergistic, or antagonistic effects of these stressors may occur. We hope our review will stimulate researchers to investigate the simultaneous effects of these and other anthropogenic stressors on the behaviour and cognition of urban‐living wild birds. [ABSTRACT FROM AUTHOR]

Language is unbounded in its generativity, enabling the flexible combination of words into novel sentences. Critically, these constructions are intelligible to others due to our ability to derive a sentence's compositional meaning from the semantic relationships among its components. Some animals also concatenate meaningful calls into compositional-like combinations to communicate more complex information. However, these combinations are structurally highly stereotyped, suggesting a bounded system of holistically perceived signals that impedes the processing of novel variants. Using long-term data and playback experiments on pied babblers, we demonstrate that, despite production stereotypy, they can nevertheless process structurally modified and novel combinations of their calls, demonstrating a capacity for deriving meaning compositionally. Furthermore, differential responses to artificial combinations by fledglings suggest that this compositional sensitivity is acquired ontogenetically. Our findings demonstrate animal combinatorial systems can be flexible at the perceptual level and that such perceptual flexibility may represent a precursor of language-like generativity. [ABSTRACT FROM AUTHOR]

The Social Intelligence Hypothesis (SIH) is one of the leading explanations for the evolution of cognition. Since its inception a vast body of literature investigating the predictions of the SIH has accumulated, using a variety of methodologies and species. However, the generalisability of the hypothesis remains unclear. To gain an understanding of the robustness of the SIH as an explanation for the evolution of cognition, we systematically searched the literature for studies investigating the predictions of the SIH. Accordingly, we compiled 103 studies with 584 effect sizes from 17 taxonomic orders. We present the results of four meta‐analyses which reveal support for the SIH across interspecific, intraspecific and developmental studies. However, effect sizes did not differ significantly between the cognitive or sociality metrics used, taxonomy or testing conditions. Thus, support for the SIH is similar across studies using neuroanatomy and cognitive performance, those using broad categories of sociality, group size and social interactions, across taxonomic groups, and for tests conducted in captivity or the wild. Overall, our meta‐analyses support the SIH as an evolutionary and developmental explanation for cognitive variation. [ABSTRACT FROM AUTHOR]

It has recently become clear that some language-specific traits previously thought to be unique to humans (such as the capacity to combine sounds) are widespread in the animal kingdom. Despite the increase in studies documenting the presence of call combinations in non-human animals, factors promoting this vocal trait are unclear. One leading hypothesis proposes that communicative complexity co-evolved with social complexity owing to the need to transmit a diversity of information to a wider range of social partners. The Western Australian magpie (Gymnorhina tibicen dorsalis) provides a unique model to investigate this proposed link because it is a group-living, vocal learning species that is capable of multi-level combinatoriality (independently produced calls contain vocal segments and comprise combinations). Here, we compare variations in the production of call combinations across magpie groups ranging in size from 2 to 11 birds. We found that callers in larger groups give call combinations: (i) in greater diversity and (ii) more frequently than callers in smaller groups. Significantly, these observations support the hypothesis that combinatorial complexity may be related to social complexity in an open-ended vocal learner, providing an important step in understanding the role that sociality may have played in the development of vocal combinatorial complexity. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'. [ABSTRACT FROM AUTHOR]

For over a century, the evolution of animal play has sparked scientific curiosity. The prevalence of social play in juvenile mammals suggests that play is a beneficial behavior, potentially contributing to individual fitness. Yet evidence from wild animals supporting the long-hypothesized link between juvenile social play, adult behavior, and fitness remains limited. In Western Australia, adult male bottlenose dolphins (Tursiops aduncus) form multilevel alliances that are crucial for their reproductive success. A key adult mating behavior involves allied males using joint action to herd individual females. Juveniles of both sexes invest significant time in play that resembles adult herding--taking turns in mature male (actor) and female (receiver) roles. Using a 32-y dataset of individual-level association patterns, paternity success, and behavioral observations, we show that juvenile males with stronger social bonds are significantly more likely to engage in joint action when play-herding in actor roles. Juvenile males also monopolized the actor role and produced an adult male herding vocalization ("pops") when playing with females. Notably, males who spent more time playing in the actor role as juveniles achieved more paternities as adults. These findings not only reveal that play behavior provides male dolphins with mating skill practice years before they sexually mature but also demonstrate in a wild animal population that juvenile social play predicts adult reproductive success. [ABSTRACT FROM AUTHOR]

Extensive research has investigated the relationship between the social environment and cognition, suggesting that social complexity may drive cognitive evolution and development. However, evidence for this relationship remains equivocal. Group size is often used as a measure of social complexity, but this may not capture intraspecific variation in social interactions. Social network analysis can provide insight into the cognitively demanding challenges associated with group living at the individual level. Here, we use social networks to investigate whether the cognitive performance of wild Western Australian magpies (Gymnorhina tibicen dorsalis) is related to group size and individual social connectedness. We quantified social connectedness using four interaction types: proximity, affiliative, agonistic and vocal. Consistent with previous research on this species, individuals in larger groups performed better on an associative learning task. However, social network position was also related to cognitive performance. Individuals receiving aggressive interactions performed better, while those involved in aggressive interactions with more group members performed worse. Overall, this suggests that cognitive performance is related to specific types of social interaction. The findings from this study highlight the value of considering fine-grained metrics of sociality that capture the challenges associated with social life when testing the relationship between the social environment and cognition. [ABSTRACT FROM AUTHOR]

Conservation translocations have become an increasingly popular method to restore or secure vulnerable populations. However, translocations greatly vary in success. The use of population viability analysis (PVA) may increase the likelihood of meeting translocation goals. However, the quality of PVAs to inform translocations is dependent on the availability of ecological data and clear translocation objectives to guide them. Here, we used PVAs to inform the planned conservation translocation of the Western Grasswren (Amytornis textilis textilis) from mainland Shark Bay onto Dirk Hartog Island, Western Australia. A range of translocation scenarios were modelled and scored against success criteria as determined by translocation objectives. Simulations of 20-yr outcomes found that a minimum founder population of 112 individuals meet all success criteria. PVA supported sourcing individuals from 2 subpopulations to maximize genetic diversity. No impact to source populations was detected for the proposed harvest quantities despite conservative estimates of initial source population sizes. Here we demonstrate that creating clear, measurable objectives alongside a PVA lessens ambiguity about which translocation scenarios could be viable. In doing so, we have identified the minimum translocation sizes needed to maintain genetic diversity and population growth, thus increasing the likelihood of translocation success without impacting the source population. [ABSTRACT FROM AUTHOR]

In the southern Kalahari Desert, cooperatively breeding Southern Pied Babblers Turdoides bicolor frequently build their nests and forage in camelthorn trees Vachellia erioloba, a keystone species in the region, and blackthorn trees Senegalia mellifera, a widespread early successional shrub. Using Ivlev's electivity indices (Ei), we show that Southern Pied Babblers preferentially nest in camelthorn trees and preferentially forage in or under camelthorn and blackthorn trees. Southern Pied Babblers primarily forage on the ground; however, they will make use of arboreal resources when these are available. We observed the birds spending the highest proportion of foraging time off the ground during October, when breeding is also most common, compared with all other months within the austral summer breeding season. They are most likely to be observed foraging in camelthorn trees earlier in the breeding season and blackthorn trees later in the breeding season. We demonstrate that Southern Pied Babblers have a strong relationship with camelthorn trees, in which they prefer to both nest and forage. We highlight the importance of protecting camelthorn trees, a keystone species in the region, as part of the conservation and management of endemic Kalahari fauna such as the Southern Pied Babbler. In addition to contributing to the literature on keystone species, our observations raise questions about the ways in which avian reproduction in the arid zone could be decoupled from rainfall via the phenology of deep‐rooted tree species. [ABSTRACT FROM AUTHOR]

Anthropogenic noise is a pollutant of growing concern, with wide‐ranging effects on taxa across ecosystems. Until recently, studies investigating the effects of anthropogenic noise on animals focused primarily on population‐level consequences, rather than individual‐level impacts. Individual variation in response to anthropogenic noise may result from extrinsic or intrinsic factors. One such intrinsic factor, cognitive performance, varies between individuals and is hypothesised to aid behavioural response to novel stressors. Here, we combine cognitive testing, behavioural focals and playback experiments to investigate how anthropogenic noise affects the behaviour and anti‐predator response of Western Australian magpies (Gymnorhina tibicen dorsalis), and to determine whether this response is linked to cognitive performance. We found a significant population‐level effect of anthropogenic noise on the foraging effort, foraging efficiency, vigilance, vocalisation rate and anti‐predator response of magpies, with birds decreasing their foraging, vocalisation behaviours and anti‐predator response, and increasing vigilance when loud anthropogenic noise was present. We also found that individuals varied in their response to playbacks depending on their cognitive performance, with individuals that performed better in an associative learning task maintaining their anti‐predator response when an alarm call was played in anthropogenic noise. Our results add to the growing body of literature documenting the adverse effects of anthropogenic noise on wildlife and provide the first evidence for an association between individual cognitive performance and behavioural responses to anthropogenic noise. [ABSTRACT FROM AUTHOR]

Global temperatures are increasing rapidly. While considerable research is accumulating regarding the lethal and sublethal effects of heat on wildlife, its potential impact on animal cognition has received limited attention. Here, we tested wild southern pied babblers (Turdoides bicolor) on three cognitive tasks (associative learning, reversal learning and inhibitory control) under naturally occurring heat stress and non-heat stress conditions. We determined whether cognitive performance was explained by temperature, heat dissipation behaviours, individual and social attributes, or proxies of motivation. We found that temperature, but not heat dissipation behaviours, predicted variation in associative learning performance. Individuals required on average twice as many trials to learn an association when the maximum temperature during testing exceeded 38°C compared with moderate temperatures. Higher temperatures during testing were also associated with reduced inhibitory control performance, but only in females. By contrast, we found no temperature-related decline in performance in the reversal learning task, albeit individuals reached learning criterion in only 14 reversal learning tests. Our findings provide novel evidence of temperature-mediated cognitive impairment in a wild animal and indicate that its occurrence depends on the cognitive trait examined and individual sex. [ABSTRACT FROM AUTHOR]

Investment in social interaction and affiliative behaviour is often related to variation in sex-specific dispersal patterns among species but can also vary within species in response to local environmental conditions and feeding competition. Chimpanzee (Pan troglodytes) association patterns have been studied primarily in low and mid-elevation tropical forests. This study adds to our understanding of association patterns in chimpanzees by presenting the first data on association patterns in a high-elevation population at Nyungwe in equatorial Rwanda. Using data on co-occurrence in social parties (party association) and calculating gregariousness indices, we quantified levels of associations among age-sex classes relative to food (fruit) distribution and the presence of oestrous females. Overall, adult females in Nyungwe are less gregarious than males. Female but not male gregariousness increased when feeding on clumped foods, indicating that resource characteristics impact female association tendencies more intensely than males. Despite high elevation forests representing a habitat with relatively fewer fruit resources for chimpanzees, at an edge of range location, we found that gregariousness patterns were driven by similar factors as those in mid and low elevation chimpanzee populations. – We quantified association patterns in a high elevation population of chimpanzees at Nyungwe (Rwanda) – Adult females were less gregarious than males – Female but not male gregariousness increased when feeding on clumped foods, indicating that resource characteristics impact female association tendencies more intensely than males [ABSTRACT FROM AUTHOR]

Cooperative breeding, where more than two individuals invest in rearing a single brood, occurs in many bird species globally and often contributes to improved breeding outcomes. However, high temperatures are associated with poor breeding outcomes in many species, including cooperative species. We used data collected over three austral summer breeding seasons to investigate the contribution that helpers make to daytime incubation in a cooperatively breeding species, the Southern Pied Babbler Turdoides bicolor , and the ways in which their contribution is influenced by temperature. Helpers spent a significantly higher percentage of their time foraging (41.8 ± 13.7%) and a significantly lower percentage of their time incubating (18.5 ± 18.8%) than members of the breeding pair (31.3 ± 11% foraging and 37.4 ± 15.7% incubating). In groups with only one helper, the helper's contribution to incubation was similar to that of breeders. However, helpers in larger groups contributed less to incubation, individually, with some individuals investing no time in incubation on a given observation day. Helpers significantly decrease their investment in incubation on hot days (>35.5°C), while breeders tend to maintain incubation effort as temperatures increase. Our results demonstrate that pied babblers share the workload of incubation unequally between breeders and helpers, and this inequity is more pronounced during hot weather. These results may help to explain why recent studies have found that larger group size does not buffer against the impacts of high temperatures in this and other cooperatively breeding species. [ABSTRACT FROM AUTHOR]

The ability to discriminate between individuals or classes of individuals based on distinctive cues is considered a vital skill in cooperative and territorial species. Here, we used playback experiments to determine whether Western Australian Magpies Gymnorhina tibicen dorsalis discriminate between the territorial carolling calls of intra‐group and extra‐group conspecifics. Magpies responded more strongly to the playback of carolling calls from extra‐group individuals than to the playback of carolling calls from intra‐group individuals, spending more time vigilant and carolling in response to extra‐group carols. Our results suggest Western Australian Magpies are able to distinguish between individuals within and outside of their social group using only vocal signals and expands on growing research reporting vocal discrimination and individual recognition abilities across species. [ABSTRACT FROM AUTHOR]

Many animals provide information about predator proximity in their alarm calls. In response to predators further away, Western Australian magpies (Gymnorhina tibicen dorsalis) produce alarm calls containing fewer notes compared to those produced when predators are closer. Since the ability to make fine-scale adjustments to antipredator responses by being sensitive to the level of urgency in calls may be beneficial, receivers are expected to be able to appropriately decipher and respond to this information. We conducted playbacks to test whether magpies can respond to urgency information in conspecific alarm calls. Magpies were exposed to low-urgency calls (calls with one note), high-urgency calls (calls with four notes), and one- and four-note control calls. Receivers showed greater levels of responsiveness following playbacks of high-urgency calls compared to playbacks of low-urgency and control calls, providing evidence that magpies can respond to information about the urgency of a predator threat from conspecific alarm calls. [ABSTRACT FROM AUTHOR]

Author(s): Benjamin J. Ashton (corresponding author) [1]; Amanda R. Ridley (corresponding author) [1]; Emily K. Edwards [1]; Alex Thornton (corresponding author) [2] The social intelligence hypothesis states that the demands [...]

Identifying the causes and fitness consequences of intraspecific variation in cognitive performance is fundamental to understand how cognition evolves. Selection may act on different cognitive traits separately or jointly as part of the general cognitive performance (GCP) of the individual. To date, few studies have examined simultaneously whether individual cognitive performance covaries across different cognitive tasks, the relative importance of individual and social attributes in determining cognitive variation, and its fitness consequences in the wild. Here, we tested 38 wild southern pied babblers (Turdoides bicolor) on a cognitive test battery targeting associative learning, reversal learning and inhibitory control. We found that a single factor explained 59.5% of the variation in individual cognitive performance across tasks, suggestive of a general cognitive factor. GCP varied by age and sex; declining with age in females but not males. Older females also tended to produce a higher average number of fledglings per year compared to younger females. Analysing over 10 years of breeding data, we found that individuals with lower general cognitive performance produced more fledglings per year. Collectively, our findings support the existence of a trade-off between cognitive performance and reproductive success in a wild bird. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.05.016 Byline: Andrew N. Radford, Amanda R. Ridley Abstract: Among the wide repertoire of vocalizations produced by social species, perhaps the most frequently heard are the 'close' calls (those of short duration and low amplitude). Despite their prevalence, and the many studies focusing on their function in primate societies, little work has been conducted on close calls in avian species. We used a combination of observations, supplementary feeding and playback experiments to investigate the function of one particular close call, the 'chuck', in group-living pied babblers, Turdoides bicolor. There was no evidence that the chuck call is used to recruit conspecifics to a food source or to reduce the likelihood of an individual becoming separated from the group. Instead, there was good evidence that it is used to regulate spacing between potential foraging competitors. Although the chuck call is not used aggressively to deter competitors that attempt to share an individual's foraging patch, it appears to indicate the forager's current position and thus minimize the likelihood of another group member approaching closely in the first place. Foragers increased their call rate in larger groups and when their nearest neighbour was closer (i.e. when foraging competition was potentially higher), and playbacks of chuck calling caused individuals to stay further away from the speaker than did background noise. Maintenance of spacing was beneficial because individuals suffered a decrease in foraging efficiency if they shared a foraging patch. This study represents one of the first experimental tests of the function of avian close calling. Author Affiliation: (a) School of Biological Sciences, University of Bristol, U.K. (a ) Percy FitzPatrick Institute, DST/NRF Centre of Excellence, University of Cape Town, South Africa Article History: Received 31 January 2007; Revised 24 April 2007; Accepted 22 May 2007 Article Note: (miscellaneous) MS. number: 9254

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.07.024 Byline: Nichola J. Raihani, Amanda R. Ridley Abstract: Giving calls to alert conspecifics to the presence of food is widespread among mammals and birds. Although the circumstances affecting the function of food-associated calls have been well studied, data on how receivers come to associate these calls with food are lacking. Specifically, the possibility that individuals may be actively taught to associate certain vocalizations with food delivery has not been addressed. In pied babblers, Turdoides bicolor, adults often give purr calls when feeding young and offspring subsequently associate these calls with food delivery. We investigated how offspring come to associate purr calls with food, specifically addressing the question of whether adults teach nestlings to respond to these calls. Adults use purr calls only in the presence of offspring and purr-calling does not seem to result in immediate, direct benefits to adults. Rather, the function of purr-calling seems to be to promote offspring learning: experimental playbacks show that nestlings learn to respond to purr calls and that purr calls must be reliably paired with food delivery for learning to occur. By giving purr calls during feeding visits at the nest, adults apparently actively condition nestlings to associate these calls with food. This represents a novel form of teaching among nonhuman animals. Author Affiliation: (a) LARG, Department of Zoology, University of Cambridge, U.K. (a ) Percy Fitzpatrick Institute of African Ornithology, University of Cape Town, South Africa Article History: Received 23 March 2007; Revised 25 June 2007; Accepted 26 July 2007 Article Note: (miscellaneous) MS. number: 9324