Ecological and evolutionary dynamics of elephant rewilding

Baker & Winkler make a thought-provoking contribution to the discussion of what role captive animals could play in nature conservation and how we could get there through rewilding. There certainly is potential for captive Asian elephants, Elephas maximus, to become targets of conservation efforts, but there are also many questions: (1) How much do (behavioral) traits of captive-origin animals differ from their free conspecifics? (2) What predicts the likelihood and strength of social reintegration of captive animals into free populations? (3) How much of an Asian elephant’s functional role in the environment can captive animals still fulfill and how may this influence the evolutionary dynamics of Asian elephant populations? These questions are challenging, but also an opportunity to gain crucial knowledge and insight into the elephant’s ecological role, as well as our own

In situ novel environment assay reveals acoustic exploration as a repeatable behavioral response in migratory bats

Integrating information on species-specific sensory perception together with spatial activity provides a high-resolution understanding of how animals explore environments, yet frequently used exploration assays commonly ignore sensory acquisition as a measure for exploration. Echolocation is an active sensing system used by hundreds of mammal species, primarily bats. As echolocation call activity can be reliably quantified, bats present an excellent animal model to investigate intra-specific variation in environmental cue sampling. Here, we developed an in situ roost-like novel environment assay for tree-cave roosting bats. We repeatedly tested 52 individuals of the migratory bat species, Pipistrellus nathusii, across 24 hours, to examine the role of echolocation when crawling through a maze-type arena and test for consistent intra-specific variation in sensory-based exploration. We reveal a strong correlation between echolocation call activity and spatial activity. Moreover, we show that during the exploration of the maze, individuals consistently differed in spatial activity as well as echolocation call activity given their spatial activity, a behavioral response we term ‘acoustic exploration’. Acoustic exploration was correlated with other exploratory behaviors, but not with emergence latency. We here present a relevant new measure for exploration behavior and provide evidence for consistent (short-term) intra-specific variation in the level at which wild bats collect information from a novel environment

Ecological and evolutionary dynamics of elephant rewilding

Baker & Winkler make a thought-provoking contribution to the discussion of what role captive animals could play in nature conservation and how we could get there through rewilding. There certainly is potential for captive Asian elephants, Elephas maximus, to become targets of conservation efforts, but there are also many questions: (1) How much do (behavioral) traits of captive-origin animals differ from their free conspecifics? (2) What predicts the likelihood and strength of social reintegration of captive animals into free populations? (3) How much of an Asian elephant’s functional role in the environment can captive animals still fulfill and how may this influence the evolutionary dynamics of Asian elephant populations? These questions are challenging, but also an opportunity to gain crucial knowledge and insight into the elephant’s ecological role, as well as our own

Data from: Migration strategy varies with novel environment response in common noctule bats

Here one can find the data files and code underlying the analysis of Schabacker et al concerning the 2019 field study on the relationship between exploration behaviour and migration in a partial migrant (Nyctalus noctula). Exploration behaviour was assessed using an in situ novel environment assay, while migration strategy was estimated using stable isotope analysis

Communication in Animal Social Networks : A Missing Link?

Animal social networks and animal communication networks are key disciplines for understanding animal social behavior, yet these disciplines remain poorly integrated. In this review, we show how communication and social networks are inherently linked, with social signals reflecting and affecting social networks. Signals carry key information on the quality and direction of social connections and reveal social connections over long distances. Moreover, social signals can directly affect proximity among conspecifics, by facilitating social attraction and repulsion. Social signals thus mediate many of the social networks we observe. Throughout, we discuss a broad range of signal types and interactions, yet with a focus on acoustic signals and show how they reflect and affect social relationships. With this review we aim to inspire further integration of the social network and communication network disciplines, expecting that it will lead to new insights into the dynamics and evolution of animal social behavior

Data from: Sex-specific responses to territorial intrusions in a communication network: evidence from radio-tagged great tits

Signals play a key role in the ecology and evolution of animal populations, influencing processes such as sexual selection and conflict resolution. In many species, sexually selected signals have a dual function: attracting mates and repelling rivals. Yet, to what extent males and females under natural conditions differentially respond to such signals remains poorly understood, due to a lack of field studies that simultaneously track both sexes. Using a novel spatial tracking system, we tested whether or not the spatial behavior of male and female great tits (Parus major) changes in relation to the response of a territorial male neighbor to an intruder. We tracked the spatial behavior of male and female great tits (N = 44), 1 hr before and 1 hr after simulating territory intrusions, employing automatized Encounternet radio-tracking technology. We recorded the spatial and vocal response of the challenged males and quantified attraction and repulsion of neighboring males and females to the intrusion site. We additionally quantified the direct proximity network of the challenged male. The strength of a male’s vocal response to an intruder induced sex-dependent movements in the neighborhood, via female attraction and male repulsion. Stronger vocal responders were older and in better body condition. The proximity networks of the male vocal responders, including the number of sex-dependent connections and average time spent with connections, did not change directly following the intrusion. The effects on neighbor movements suggest that the strength of a male’s vocal response can provide relevant social information to both the males and the females in the neighborhood, resulting in both sexes adjusting their spatial behavior in contrasting ways, while the social proximity network remained stable. Moreover, our study underlines the importance of the “silent” eavesdroppers within communication networks for studying the dual functioning and evolution of sexually selected signals

Data from: Dominance rank and boldness predict social attraction in great tits

Social relationships can have important fitness consequences, and how well an individual is socially connected often correlates with other behavioral traits. Whether such correlations are caused by underlying individual differences in social attraction usually remains unclear, because to identify effects of individual traits on social attraction, it is essential to experimentally exclude the influence of the social partner. Using standardized high-definition video playback on captive great tits (Parus major), we effectively demonstrate the influence of individual traits on the motivation to be near a conspecific. We show that social attraction varied contrastingly with boldness and stimulus novelty. Shyer birds tended to show stronger social attraction when they were confronted with the stimulus bird for the first time. Lower ranked birds showed the overall strongest social attraction. This rank effect remained after experimentally changing dominance ranks by altering group compositions. Moreover, preference for social association tended to increase with a decrease in dominance rank, suggesting that birds plastically change their social preference in relation to their within-group dominance status. Our results provide insight into how social relations can form and change, processes that are key for understanding the long-term consequences of the social environment, and the role individuals might play in influencing this environment themselves

Dominance rank and boldness predict social attraction in great tits

Social relationships can have important fitness consequences, and how well an individual is socially connected often correlates with other behavioral traits. Whether such correlations are caused by underlying individual differences in social attraction usually remains unclear, because to identify effects of individual traits on social attraction, it is essential to experimentally exclude the influence of the social partner. Using standardized high-definition video playback on captive great tits (Parus major), we effectively demonstrate the influence of individual traits on the motivation to be near a conspecific. We show that social attraction varied contrastingly with boldness and stimulus novelty. Shyer birds tended to show stronger social attraction when they were confronted with the stimulus bird for the first time. Lower ranked birds showed the overall strongest social attraction. This rank effect remained after experimentally changing dominance ranks by altering group compositions. Moreover, preference for social association tended to increase with a decrease in dominance rank, suggesting that birds plastically change their social preference in relation to their within-group dominance status. Our results provide insight into how social relations can form and change, processes that are key for understanding the long-term consequences of the social environment, and the role individuals might play in influencing this environment themselves.</p

Repeatability of signalling traits in the avian dawn chorus

Background: Birdsong, a key model in animal communication studies, has been the focus of intensive research. Song traits are commonly considered to reflect differences in individual or territory quality. Yet, few studies have quantified the variability of song traits between versus within individuals (i.e. repeatability), and thus whether certain song traits indeed provide reliable individual-specific information. Here, we studied the dawn chorus of male great tits (Parus major) to determine if key song traits are repeatable over multiple days and during different breeding stages. Additionally, we examined whether repeatability was associated with exploration behaviour, a relevant personality trait. Finally, we tested if variation in song traits could be explained by breeding stage, lowest night temperature, and exploration behaviour. Results: We show that the start time of an individual's dawn song was indeed repeatable within and across breeding stages, and was more repeatable before, than during, their mate's egg laying stage. Males started singing later when the preceding night was colder. Daily repertoire size was repeatable, though to a lesser extent than song start time, and no differences were observed between breeding stages. We did not find evidence for an association between exploration behaviour and variation in dawn song traits. Repertoire composition, and specifically the start song type, varied across days, but tended to differ less than expected by chance. Conclusions: Our findings that individuals consistently differ in key song traits provides a better understanding of the information receivers can obtain when sampling songs of different males. Surprisingly, start time, despite being influenced by a highly variable environmental factor, appeared to be a more reliable signal of individual differences than repertoire size. Against expectation, singers were more repeatable before than during their mate's egg laying stage, possibly because before egg laying, females are less constrained to move around unguarded and thus may then already sample (and compare) different singers. Combining repeated dawn song recordings with spatial tracking could reveal if the sampling strategies of receivers are indeed important drivers of repeatability of song traits. Such a complementary approach will further advance our insights into the dynamics and evolution of animal signalling systems.</p

Effectiveness of animal conditioning interventions in reducing human–wildlife conflict: a systematic map protocol

BACKGROUND: Human–wildlife conflict (HWC), is currently one of the most pressing conservation challenges. We restrict ourselves here to wildlife behaviour that is perceived to negatively impact social, economic or cultural aspects of human life or to negatively impact species of conservation concern. HWC often involves wild animals consuming anthropogenic resources, such as crops or livestock, either out of necessity (loss of habitat and natural prey) or as consequence of opportunistic behaviour. A variety of interventions are undertaken to reduce HWC, differing in practicability, costs and social acceptance. One such non-lethal intervention is animal conditioning, a technique to reduce conflict by modifying the behaviour of ‘problem’ animals long-term. Conditioning changes associations animals have with resources or behaviours. Both via ‘punishment’ of unwanted behaviour and ‘rewarding’ of alternative behaviour, researchers aim to make expression of unwanted behaviour relatively less desirable to animals. Despite the potential, however, studies testing conditioning interventions have reported seemingly contradictory outcomes. To facilitate reduction of HWC via conditioning, we thus need to better understand if and when conditioning interventions are indeed effective. With this systematic map we intend to make the global evidence base for conditioning of free-ranging vertebrates more accessible to practitioners, to identify potential evidence clusters and effect modifiers for a subsequent systematic review and to highlight evidence gaps for future research. METHODS: We will compile evidence, including grey literature, from bibliographic databases, online search engines, specialist sites and expert contacts. Where possible, a Boolean-style full search string will be used, including Intervention and Outcome search terms. Searches will be conducted in English. Search comprehensiveness will be evaluated with an a priori list of benchmark articles. We will base inclusion of articles on presence of quantitative data, subject identity, comparator and outcome. Inclusion consistency checks will be performed with 10% of the titles, abstracts and full texts. We will assess validity of the literature base on basis of study design and sample size. Finally, we will develop a searchable literature database and an interactive evidence atlas along with a narrative synthesis of the evidence