Showing papers in "Behavioral Ecology in 2017"
TL;DR: It is demonstrated how alternative approaches enable behavioural ecologists to test hypotheses about the causes and consequences of individual behavioural variation while accounting for the uncertainty inherent in the random effects.
Abstract: Having recognized that variation around the population-level "Golden Mean" of labile traits contains biologically meaningful information, behavioural ecologists have focused increasingly on exploring the causes and consequences of individual variation in behaviour. These are exciting new directions for the field, assisted in no small part by the adoption of mixed-effects modelling techniques that enable the partitioning of among- and within-individual behavioural variation. It has become commonplace to extract predictions of individual random effects from such models for use in subsequent analyses (for example, between a personality trait and other individual traits such as cognition, physiology, or fitness-related measures). However, these predictions are made with large amounts of error that is not carried forward, rendering further tests susceptible to spurious P values from these individual-level point estimates. We briefly summarize the problems with such statistical methods that are used regularly by behavioural ecologists, and highlight the robust solutions that exist within the mixed model framework, providing tutorials to aid in their implementation.
198 citations
TL;DR: It is argued that the field of animal personality does not add anything new and appears to be a rebranding of much more rigorous fields of research.
Abstract: Lay Summary We know that animals differ in their behavior. What we do not know is why the study of animal personalities is apparently the only way by which we can understand individual differences among animals. We argue that the field of animal personality does not add anything new. Instead, it appears to be a rebranding of much more rigorous fields of research.
84 citations
TL;DR: Using GPS-radio collar data from 98 brown bears, it is shown that bears, in fact, differ in their activity tactic and 4 distinct tactics from strictly day active to strictly night active are illustrated.
Abstract: There is a growing recognition of the role of individual variation in patterns emerging at higher levels of biological organization. Despite the importance of the temporal configuration of ecological processes and patterns, intraspecific individual variation in diel activity patterns is almost never accounted for in behavioral studies at the population level. We used individual-based monitoring data from 98 GPS-collared brown bears in Scandinavia to estimate diel activity patterns before the fall hunting season. We extracted 7 activity measures related to timing and regularity of activity from individual activity profiles. We then used multivariate analysis to test for the existence of distinct activity tactics and their environmental determinants, followed by generalized linear regression to estimate the extent of within-individual repeatability of activity tactics. We detected 4 distinct activity tactics, with a high degree of individual fidelity to a given tactic. Demographic factors, availability of key foraging habitat, and human disturbance were important determinants of activity tactics. Younger individuals and those with higher bear and road densities within their home range were more nocturnal and more likely to rest during the day. Good foraging habitat and increasing age led to more diurnal activity patterns and nocturnal resting periods. We did not find evidence of diel activity tactics influencing survival during the subsequent hunting season. We conclude that individual variation in activity deserves greater attention than it currently receives, as it may help account for individual heterogeneity in fitness and could facilitate within-population niche partitioning that can have population- or community-level consequences.
67 citations
TL;DR: It is argued that using a single umbrella term that incorporates too many unrelated traits should be avoided in behavioral flexibility assessments, especially in behavioral ecology.
Abstract: Behavioral flexibility is measured using a plethora of non-equivalent tasks. In experimental psychology, tests include reversal learning, set-shifting and self-control tasks. In addition to the latter tasks, behavioral ecologists have measured behavioral flexibility with tasks that include problem-solving and personality tests. A relationship between behavioral flexibility assessments, especially in behavioral ecology, still needs to be demonstrated. We argue that using a single umbrella term that incorporates too many unrelated traits should be avoided.
67 citations
TL;DR: This paper aims to demonstrate the efforts towards in-situ applicability of EMMARM, as to provide real-time information about concrete mechanical properties such as E-modulus and compressive strength, which are important for efficient and effective storage.
Abstract: REF Compliant by Deposit in other institution's Repository: Durham's repository on 24/04/2017: http://dro.dur.ac.uk/21580/
54 citations
TL;DR: Findings suggest that individual network position can be a consistent property of individuals that is resilient to disturbance and could experience selection in a predictable fashion, however, group network structure seems to change over time unless reset by disturbance.
Abstract: Social networks encompass both individual and group phenotypes that have been shown to covary with fitness in several species. In order for network characters to be evolutionarily important, they must reliably reflect properties of an individual or groups of individuals; however, it is unknown whether network traits are consistently expressed at either level. To determine if measurable components of individual social network position were repeatable and if the network structure as a whole was consistent in Bolitotherus cornutus (the forked fungus beetle), we constructed 8 experimental populations. Half of the populations were disturbed between 2 observation periods. Two individual network metrics (strength and betweenness) were significantly repeatable across time in all treatments; a third (clustering coefficient) was not. At the network level, all 3 metrics changed more in undisturbed than disturbed networks. These findings suggest that individual network position can be a consistent property of individuals that is resilient to disturbance and could experience selection in a predictable fashion. However, group network structure seems to change over time unless reset by disturbance.
54 citations
TL;DR: It is proposed that resource dynamics reinforce differences via influence on fission–fusion processes, which is termed “ecological release,” and implications for conservation and management when animals are spatially constrained are discussed.
Abstract: Dominance hierarchies are expected to form in response to socioecological pressures and competitive regimes. We assess dominance relationships among free-ranging female Asian elephants (Elephas maximus) and compare them with those of African savannah elephants (Loxodonta africana), which are known to exhibit age-based dominance hierarchies. Both species are generalist herbivores, however, the Asian population occupies a more productive and climatically stable environment relative to that of the African savannah population. We expected this would lower competition relative to the African taxon, relaxing the need for hierarchy. We tested whether 1) observed dominance interactions among individuals were transitive, 2) outcomes were structured either by age or by social unit according to 4 independent ranking methods, and 3) hierarchy steepness among classes was significant using David's score. Elephas maximus displayed less than a third the number of dominance interactions as observed in L. africana, with statistically insignificant transitivity among individuals. There was weak but significant order as well as steepness among age-classes but no clear order among social units. Loxodonta africana showed significant transitivity among individuals, with significant order and steepness among age-classes and social units. Elephas maximus had a greater proportion of age-reversed dominance outcomes than L. africana. When dominance hierarchies are weak and nonlinear, signals of dominance may have other functions, such as maintaining social exclusivity. We propose that resource dynamics reinforce differences via influence on fission-fusion processes, which we term "ecological release." We discuss implications of these findings for conservation and management when animals are spatially constrained.
53 citations
TL;DR: Eastern chipmunks in urban habitats had significantly different behavior, tending toward reduced locomotion and grooming, and greater latency, than their counterparts from natural habitats, suggesting that urban habitats may be relatively benign for urbanChipmunks.
Abstract: Cities are rapidly expanding, and wildlife may experience different selection pressures in urban environments when compared to natural habitats. Phenotypic differences between urban and natural populations may occur because of the altered urban environment. Behavior, the activity of the hypothalamic-pituitary-adrenal (HPA) axis and body condition can be expected to differ between urban and natural habitats. We used the eastern chipmunk (Tamias striatus) to test for differences in behavior assayed from an open field test, hair and fecal cortisol concentrations, and body condition (size-corrected body mass), predicting that urban chipmunks would exhibit more exploratory behavior, higher cortisol concentrations, and higher body condition, than their counterparts from natural habitats. We sampled eastern chipmunks in 2 urban areas paired with natural habitats and subjected adult chipmunks to an open field test, collected hair and fecal samples for the determination of cortisol concentrations, and measured body size and body mass to estimate body condition. Eastern chipmunks in urban habitats had significantly different behavior, tending toward reduced locomotion and grooming, and greater latency, than their counterparts from natural habitats. Urban chipmunks also had lower fecal cortisol concentrations than those from natural habitats, and female chipmunks were in better body condition when captured in urban habitats. These results suggest that urban habitats may be relatively benign for urban chipmunks, perhaps because of reduced need for exploration and the availability of anthropogenic food subsidies associated with urban environments.
52 citations
TL;DR: Widespread poaching of large ungulates may increase levels of competition between lions and leopards by forcing them to target the same prey.
Abstract: Lay SummaryWe tested the population-level effects of a dominant competitor—lions—on a subordinate—leopards. Although lions were a common cause of leopard mortality, they did not suppress or displace leopards. Population growth was similar between the 2 species and leopards did not avoid lions. Coexistence was likely possible because lions and leopards targeted different sized prey. Widespread poaching of large ungulates may increase levels of competition between lions and leopards by forcing them to target the same prey.
51 citations
TL;DR: The giant panda’s extrordinary pelage coloration has several different functions, finding that white fur on the body is for matching white snowy backgrounds, black fur on legs is for camouflage in shade, but that markings on the face are for communication to other pandas or to would-be predators.
Abstract: Lay Summary We use comparative information on carnivores and bear subspecies to investigate coloration of the giant panda. We find that white fur on the body is for matching white snowy backgrounds, black fur on legs is for camouflage in shade, but that markings on the face are for communication to other pandas or to would-be predators. The giant panda’s extrordinary pelage coloration has several different functions.
49 citations
TL;DR: This paper discusses how the Transparency and Openness Promotion guidelines, proposed by the Center for Open Science, along with a software engineering toolkit allow researchers to embrace the open science process.
Abstract: Science is meant to be the systematic and objective study of the world but evidence suggests that scientific practices are sometimes
falling short of this expectation. In this invited idea, we argue that any failure to conduct research according to a documented plan
(lack of reliability) and/or any failure to ensure that reconducting the same project would provide the same finding (lack of reproducibility),
will result in a low probability of independent studies reaching the same outcome (lack of replicability). After outlining the
challenges facing behavioral ecology and science more broadly and incorporating advice from international organizations such as the
Center for Open Science (COS), we present clear guidelines and tutorials on what we think open practices represent for behavioral
ecologists. In addition, we indicate some of the currently most appropriate and freely available tools for adopting these practices.
Finally, we suggest that all journals in our field, such as Behavioral Ecology, give additional weight to transparent studies and therefore
provide greater incentives to align our scientific practices to our scientific values. Overall, we argue that producing demonstrably
credible science is now fully achievable for the benefit of each researcher individually and for our community as a whole.
TL;DR: Bird species that allopreen were more likely to share parental duties and more likelihood to breed with the same partner in consecutive breeding seasons, compared to species that do not allopreens.
Abstract: Individuals of many species form bonds with their breeding partners, yet the mechanisms maintaining these bonds are poorly understood. In birds, allopreening is a conspicuous feature of interactions between breeding partners and has been hypothesized to play a role in strengthening and maintaining pair bonds within and across breeding attempts. Many avian species, however, do not allopreen and the relationship between allopreening and pair bonding across species remains unexplored. In a comparative analysis of allopreening and pair bond behavior, we found that allopreening between breeding partners was more common among species where parents cooperate to rear offspring. The occurrence of allopreening was also associated with an increased likelihood that partners would remain together over successive breeding seasons. However, there was no strong evidence for an association between allopreening and sexual fidelity within seasons or time spent together outside the breeding season. Allopreening between partners was also no more common in colonial or cooperatively breeding species than in solitary species. Analyses of evolutionary transitions indicated that allopreening evolved from an ancestral state of either high parental cooperation or high partner retention, and we discuss possible explanations for this. Overall, our results are consistent with an important role for allopreening in the maintenance of avian pair bonds.
TL;DR: This paper presents a meta-analyses of birdwatchers’ responses to the Hochachka virus, which has the potential to provide real-time insights into the behaviour of birds of prey and provides a basis for future generations of ornithologists to study these birds.
Abstract: The study of aggressive interactions between species has, to date, usually been restricted to interactions among small numbers of ecologically close competitors. Nothing is known about interspecific dominance hierarchies that include numerous, ecologically varied species. Such hierarchies are of interest because they could be used to address a variety of research questions, e.g. do similarly ranked species tend to avoid each other in time or space, and what will happen when such species come into contact as climates change? Here, we propose a method for creating a continental-scale hierarchy, and we make initial analyses based on this hierarchy. We quantified the extent to which a dominance hierarchy of feeder birds was linear, as intransitivities can promote local species9 coexistence. Using the existing network of citizen scientists participating in Project FeederWatch, we collected the data with which to create a continent-spanning interspecific dominance hierarchy that included species that do not currently have overlapping geographic distributions. Overall, the hierarchy was nearly linear, and largely predicted by body mass, although there were clade-specific deviations from the average mass-dominance relationship. Most of the small number of intransitive relationships in the hierarchy were based on small samples of observations. Few observations were made of interactions between close relatives and ecological competitors like Melanerpes woodpeckers and chickadees, as such species often have only marginally overlapping geographic distributions. Yet, these species9 ranks--emergent properties of the interaction network--were usually in agreement with published literature on dominance relationships between them.
TL;DR: The findings question the common interpretation that differences between forest and city areas relate to specific environmental axes that covary with urbanization, especially in in lieu of quantitative measurements.
Abstract: Optimal life-history decisions are shaped by prevailing environmental conditions. In the context of urbanization, environmental differences between urban and rural areas are known to vary across a multitude of axes. The relative roles of specific axes and whether they explain variation in avian life histories between forest and city populations have not often been studied empirically. This study comprehensively views urbanization from a multidimensional environmental perspective. For each of 13 nest box plots of a common passerine bird (the great tit Parus major), we quantified temperature, humidity, light, and noise, and subsequently assessed direct versus indirect effects of each environmental axis on components of annual reproductive success by applying a path analytical framework. All quantified environmental axes, and life-history traits, showed substantial repeatable variation between the plots. Forest and city plots differed tremendously in temperature, humidity, and light. We were able to attribute among-population variation in life history to variation in these environmental effects. However, the simple dichotomy between forest and city populations explained the data best. Birds in the city laid earlier, which indirectly resulted in smaller clutches, and their offspring fledged in poorer condition, compared to conspecifics in forests. Those differences persisted after controlling for temperature, humidity, light, and noise, which implies that they were shaped by other factors than the ones quantified in this study. In summary, our findings question the common interpretation that differences between forest and city areas relate to specific environmental axes that covary with urbanization, especially in in lieu of quantitative measurements.
TL;DR: It is shown that predation risk is a cost of the sexually selected red coloration of the threespine stickleback and, hence, could contribute to signal honesty.
Abstract: Lay SummaryThe factors that limit sexual signal expression and ensure honest signaling of mate quality are poorly known We show that predation risk is a cost of the sexually selected red coloration of the threespine stickleback and, hence, could contribute to signal honesty A common predator selectively preys on colorful stickleback males in the field, and an experimental study showed that the bright coloration attracts the predator independent of the behavior of the male
TL;DR: The hypothesis that masculine male faces or feminine female faces are more attractive in environments with higher exposure to malarial pathogens or urban development is found no support, but preferences for facial symmetry were highest in islands with higher malarial rates.
Abstract: Prevailing environmental factors influence preferences for attractive traits across many species. In humans, debate surrounds the role of environmental pathogens and economic development in determining facial attractiveness. We tested whether women and men's preferences for facial dimorphism, symmetry, skin tone, and adiposity differ among Melanesian participants from 3 islands (Espiritu Santo, Efate, and Tanna) in Vanuatu in the South West Pacific. These islands vary in their historical malarial pathogens respectively from pronounced to almost absent and are characterized by within and between island differences in economic development, ranging from urbanized market-based economies to remote rural horticultural communities. We found no support for the hypothesis that masculine male faces or feminine female faces are more attractive in environments with higher exposure to malarial pathogens or urban development. However, preferences for facial symmetry were highest in islands with higher malarial rates, possibly as symmetry indicates health and guides mate selection in disease rich environments. However, past evidence linking symmetry and health is weak, and we therefore interpret our findings cautiously. Women from peri-urban communities preferred male faces with lighter skin to rural and urban participants. Men from urban areas stated higher preferences for symmetry than peri-urban and rural male participants. All other effects were not statistically significant. While cross-cultural studies comparing preferences between disparate cultures provide evidence of associations between environmental effects and preferences for some facial traits, our results suggest these associations might not always persist at more fine-grain scales within small-scale societies.
TL;DR: It is shown that the Icelandic population, which feeds on herring, presents a multilevel society with no clear hierarchical stratification nor coherent social groups, suggesting that local ecological characteristics such as traits of the target prey and employed foraging strategy may be important drivers in shaping the social structure of the species.
Abstract: This work was supported by the Fundacao para a Ciencia e a Tecnologia (grant numbers SFSFRH/BD/30303/2006 and SFRH/BD/84714/2012); Icelandic Research Fund (i. Rannsoknasjođur, grant number 120248402); National Geographic Society Science and Exploration Europe (grant number GEFNE65-12); Office of Naval Research (grant number N00014-08-10984); and a Russell Trust Award from the University of St. Andrews.
TL;DR: It is found that Italian free-ranging dogs live in packs with a stable membership and with a clear hierarchical social structure, and high social status in dogs was mainly held by elders, and agonistic interactions were highly ritualized.
Abstract: Lay SummaryContrary to the view that social dominance is a wolf feature that was lost by dogs during domestication, we found that Italian free-ranging dogs live in packs with a stable membership and with a clear hierarchical social structure. Moreover, as in wolves and other cooperative animals in which group members rely on the guidance of experienced companions, high social status in dogs was mainly held by elders, and agonistic interactions were highly ritualized.
TL;DR: This work quantified features of the acrobatic, multimodal “leap display” of blue-black grassquits (Volatinia jacarina) and provided evidence that display attributes that emphasize vigor and skill may limit one another.
Abstract: Animal social behaviors are often mediated by signals that provide information about signaler attributes. Although some signals are structurally simple, others are temporally dynamic and multifaceted. In such cases, exaggeration of some display components is likely to curtail the expression of others. We quantified features of the acrobatic, multimodal “leap display” of blue-black grassquits (Volatinia jacarina), which appears to entail moderate-to-high performance levels in terms of vigor and skill. We video recorded and quantified leap parameters (height, duration, rotation angle, launch velocity, and number of wing beats) and assessed how these parameters covaried with each other and with vocal parameters, display rates, and body mass index. Our analyses revealed correlations among multiple performance variables: leap height, duration, launch velocity, and number of wing beats. Leap height also correlated positively with song duration. By contrast, no leap parameters covaried with rotation angle. Our analyses also revealed a trade-off in vigor and skill-based leap attributes: birds with a lower body mass index showed a negative relationship between leap heights and the proportion of displays that included leaps (vs. perched vocalizations only). Our results identify directions of display evolution subject to mechanical or timing constraints and provide evidence that display attributes that emphasize vigor and skill may limit one another. Our results also support a key expectation of handicap models of display evolution, which is that costs of display execution should be borne disproportionately by signalers of lower quality.
TL;DR: It is demonstrated that flexible and effective pollen collection by bees is regulated by 2 ubiquitous floral cues, which means that effective flexibility in pollen collection can occur without necessitating learning.
Abstract: Lay SummaryLearning enables generalists to forage efficiently from diverse floral resources. Bees must collect nectar and pollen, but effective, flexible foraging behavior has been demonstrated only for nectar foragers. We demonstrate that flexible and effective pollen collection by bees is regulated by 2 ubiquitous floral cues. This mechanism of foraging flexibility likely facilitated the evolution of pollen concealment via poricidal floral morphology. We conclude that effective flexibility in pollen collection can occur without necessitating learning.
TL;DR: Experimental evidence is provided to confirm that the common cuckoo locates its Oriental reed warbler host nests by monitoring the activities of nest owners and distinguishes between nest types of different host species.
Abstract: Lay Summary We provide experimental evidence to confirm that the common cuckoo (Cuculus canorus) locates its Oriental reed warbler (Acrocephalus orientalis) host nests by monitoring the activities of nest owners. Cuckoos distinguished between nest types of different host species and choose to parasitize nests of the most commonly parasitized host, while cuckoos did not choose to lay eggs in nests matching the appearance of their own eggs.
TL;DR: It is shown that personality can be used to predict both survival and ability to engage in beneficial behaviours after release in tortoises about to be released into the wild.
Abstract: Lay SummaryPersonality is a fundamental component of the individual although atypically considered during conservation efforts. For tortoises about to be released into the wild, we quantified personality prior to release and related it to survival and behaviour in their new environments. We show that personality can be used to predict both survival and ability to engage in beneficial behaviours after release. Personality and behaviour may provide meaningful guidance to conservation practitioners.
TL;DR: Considering allometric relationships between body size and RHP traits may lead to new insights in animal contest theory and may help to solve discrepancies between current theory and empirical data.
Abstract: Lay Summary How do animals decide to give up on a fight? Fighting ability is central to the answer, and we may be assuming that it increases linearly with body size, when that may not be entirely true. Here, we adapt a framework for analyzing fights to allow fighting ability to increase exponentially with body size. We show that when that assumption is considered, the answer may differ.
TL;DR: It is shown that using other species as cues for good breeding sites also occurs between migrants, and wood warblers use a combination of personal information, and cues based on individuals of the same and different species to make settlement decisions.
Abstract: Lay Summary A late arriving migrant bird species (wood warbler) are attracted to simulated presence of an earlier arriving species (chiffchaff). This habitat selection strategy was previously only described for migrants attracting to resident species, but we show that using other species as cues for good breeding sites also occurs between migrants. Wood warblers use a combination of personal information, and cues based on individuals of the same and different species to make settlement decisions.Twitter: @szymkowiakj
TL;DR: It is shown that adult sex ratio and operational sex ratio fluctuate over the breeding season and these fluctuations are not correlated, suggesting that OSR is a poor predictor of ASR under polygamy.
Abstract: Lay Summary Sex ratios vary within wild populations, but these variations and the relationship of different sex ratio indices are rarely explored. Using data from a well-monitored polygamous bird population, we show that adult sex ratio (ASR, proportion of males in adult population) and operational sex ratio (OSR, ratio of sexually active males to females) fluctuate over the breeding season and these fluctuations are not correlated, suggesting that OSR is a poor predictor of ASR under polygamy.
TL;DR: It is demonstrated that subtle differences in the quality of the environment experienced early in life can influence how individuals negotiate behavioral and life-history trade-offs later in life and changes in the developmental environment are not sufficient to collapse behavioral syndromes.
Abstract: Lay Summary Understanding behavioral differences in animals is a complex task as many factors play a strong role in shaping these differences. Here, we show that house crickets exposed to a low quality diet over development expressed stronger differences among individuals relative to within individuals when responding to predator cues, compared to individuals exposed to a high quality diet. Our research stresses the importance of variation in developmental environment when investigating factors affecting behavioral variation.Twitter: @RRoyaute
TL;DR: This paper aims to demonstrate the efforts towards in-situ applicability of EMMARM, as to provide real-time information about concrete mechanical properties such as E-modulus and compressive strength.
Abstract: Funding: NERC (NE/D010365/1) and European Research Council advanced grants (EVOCULTURE 232823).
TL;DR: The results suggest that consistent individual differences in cognitive performance along with consistent differences in personality could determine response to environmental change and therefore have important fitness consequences.
Abstract: To study the fitness effects of individual variation in cognitive traits, it is paramount to understand whether traits such as personality and physiological stress influence cognitive performance We first tested whether budgerigars showed both consistent personalities and cognitive performance across time and tasks We tested object and food neophobia, and exploratory behavior We measured cognitive performance in habituation, ability to solve foraging problems, spatial memory, and seed discrimination tasks Budgerigars showed consistency in their neophobic tendencies and these tendencies were associated with their exploratory behavior Birds were also consistent in how they performed in most of the cognitive tasks (temporal consistency), but were not consistent in their performance across tasks (context consistency) Neither corticosterone levels (baseline and stress-induced) showed a significant relationship with either cognitive or personality measures Neophobic and exploratory tendencies determined the willingness of birds to engage only in the seed discrimination task Such tendencies also had a significant effect on problem-solving ability Our results suggest that consistent individual differences in cognitive performance along with consistent differences in personality could determine response to environmental change and therefore have important fitness consequences
TL;DR: Using fish as predators presented with simulations of virtual prey, it is shown that prey on the edge of groups are more likely to be attacked than others, even at relatively small group sizes.
Abstract: Marginal predation, also known as the edge effect, occurs when aggregations of prey are preferentially targeted on their periphery by predators and has long been established in many taxa. Two main processes have been used to explain this phenomenon, the confusion effect and the encounter rate between predators and prey group edges. However, it is unknown at what size a prey group needs to be before marginal predation is detectable and to what extent each mechanism drives the effect. We conducted 2 experiments using groups of virtual prey being preyed upon by 3-spined sticklebacks (Gasterosteus aculeatus) to address these questions. In Experiment 1, we show that group sizes do not need to be large for marginal predation to occur, with this being detectable in groups of 16 or more. In Experiment 2, we find that encounter rate is a more likely explanation for marginal predation than the confusion effect in this system. We find that while confusion does affect predatory behaviors (whether or not predators make an attack), it does not affect marginal predation. Our results suggest that marginal predation is a more common phenomenon than originally thought as it also applies to relatively small groups. Similarly, as marginal predation does not need the confusion effect to occur, it may occur in a wider range of predator-prey species pairings, for example those where the predators search for prey using nonvisual sensory modalities.
TL;DR: In the wild zebra finch, parents produce vocal duets each time they meet at the nest and the acoustic structure of these duets is measured and it is shown that birds call differently before leaving or staying in the nest.
Abstract: Bi-parental care may involve both cooperation and conflict between parents. Parents adjust their workload to that of their partner and this ability is likely to affect reproductive success. Whether mates communicate, either to resolve the sexual conflict or to coordinate their joint investment in parental care is a largely unaddressed question which we examined by recording wild zebra finches at the nest during incubation. Zebra finch (Taeniopygia guttata) partners produce vocal exchanges at the nest that can be characterized as duets. Some duets end in nest-relief (when birds take turns incubating and foraging) but some do not (when the foraging mate vocally interacts with its incubating partner by coming inside or in the vicinity of the nest). Our data indicate that the structure of the duet predicted its outcome (relief or not), with a parent calling differently before leaving or staying in the nest by modifying its vocal repertoire as well as the acoustic structure of one particular call type which is typically used inside the nest. Zebra finch partners may thus exchange on the time to take turns with parental duties. Our results show that acoustic communication between partners might be of importance in the organization of parental care and could help in understanding sexual conflict resolution or cooperation phenomena in future studies.