Biology subjects

Penndorf, J.

Publications and source records attributed to Penndorf, J..

8 recordsLinked to original sources

bioRxiv2025

Sex-dependent carry-over between winter associations and breeding proximity in a communally roosting parrot

Between-season carry-over in social associations is widely observed and can have important benefits for individuals, ranging from reduced conflict between neighbours to cooperative nest defence. Yet the underlying drivers of social carry-over effects remain unclear, as current research has predominantly focused on species where breeding territories are influenced by individuals non-breeding spatial distribution, making it challenging to disentangle social and spatial preferences. Sulphur-crested cockatoos (Cacatua galerita) form communal night-roosts with fission-fusion dynamics around the roost-site. During spring, breeding individuals split from the roost to occupy nearby tree hollows, but remain non-territorial, allowing us to test whether individuals exhibit a preference to breed in proximity to winter social associates. We find that male--but not female-- winter social associations are correlated with breeding location; males bred closer to their winter associates, and more socially connected males tended to breed closer to the roost location. Male cockatoos are largely philopatric to their natal roost, and exhibit long-lasting foraging associations, preferentially with kin. Our results demonstrate carry-over between these social networks and the fine-scale arrangement of breeding individuals, consistent with an active choice to retain stable, across-context social relationships.

animal behavior and cognition↗

bioRxiv2025

Social and ecological factors associated with innovation in urban sulphur-crested cockatoos (Cacatua galerita)

Why some species thrive in urban environments while others do not is a central question in behavioral ecology. Behavioral innovations has been proposed as a key mechanism facilitating this adaptation. At the individual level, innovativeness varies with cognitive and behavioral traits. However, at the population level, innovation rates can also be influenced by social and ecological factors including group size, and environmental novelty and complexity. The role of these factors are still under-explored, especially at within-city scales. To disentangle factors influencing group-level variation in innovation rates, we presented roosts of wild sulphur-crested cockatoos Cacatua galerita, with extractive-foraging tasks that required innovative problem-solving. We installed three tasks of different levels of difficulty on trees at fifteen communal roost sites across an urban matrix. We matched these with direct measures of roost-size and connectivity, and with high-resolution remote-sensing mapping to estimate variation in urbanization and environmental heterogeneity. We found that approach time was significantly associated with urbanization, with individuals in more urban sites approaching tasks more quickly, suggesting reduced neophobia with urbanization or increased familiarity with human-derived objects. In contrast, time to innovate in our study was explained by task difficulty rather than environmental and social factors. While we detected no significant effects of group size, connectivity, and environmental heterogeneity, larger sample sizes may be needed to reveal more subtle influences on innovation. Together, these results suggest that urbanization gradients can shape behavioral responses to novelty independently from problem-solving abilities. Lay SummaryCities are challenging places for wildlife, but some species, like sulphur-crested cockatoos, adapt by finding new ways to feed and solve problems. We studied how urbanization and social factors vary with cockatoos ability to innovate when presented with extractive-foraging tasks. We found that birds in more urban areas approached the tasks more quickly, suggesting reduced neophobia or increased familiarity with novel objects. This work highlights behavioral differences across urbanization gradients in human-dominated environments.

animal behavior and cognition↗

bioRxiv2025

To preen or not to preen: social predictors of allopreening in a wild parrot

Allogrooming is fundamental to social relationships in many group-living mammals. In primates, allogrooming has been the subject of decades of research, and has been shown to play an essential role in maintaining social affiliations, and often interchanged for social tolerance and support. Yet, while the equivalent behaviour of allopreening occurs in many avian species, most description has been limited to its role in pair formation and maintenance, with little known about non-pair contexts. Here we investigated the decision-making associated with allopreening in wild sulphur-crested cockatoos, conducting detailed observations of 182 allopreening events between 126 individuals while concurrently recording rank, aggressive interactions, and social networks. We found no influence of sex as predicted if allopreening was primarily about pair bonding, but instead a positive correlation between allopreening and aggression (given and received). Within interactions, individuals were influenced by social association strength and rank, with individuals preening for longer and with more turn-taking when interacting with stronger social associates, and individuals investing more in interactions initiated by higher-ranked individuals. Our results are highly suggestive that allopreening may serve a convergent function in wild parrots to primates, both in maintaining social bonds and in negotiating social tolerance.

animal behavior and cognition↗

bioRxiv2024

Low-cost animal tracking using Bluetooth low energy beacons on a crowd-sourced network

O_LIAnimal tracking has opened the door to address many fundamental questions in ecology and conservation. While historically animals have been tracked as a means to understand their large-scale movements, such as migration, there is now a greater focus on using tracking to study movements over smaller scales, individual variation in movement, or how movements shape social network structure. With this shift in focus also comes different tracking needs, including the need to track larger numbers of individuals. C_LIO_LITracking studies all face some technological limitations. For example, GPS and other active tracking solutions can collect fine-scale movement data, but have a high cost per tag, limiting the number of individuals that can be followed. They also have high energy costs of data acquisition and download, limiting time periods over which data can be collected. Low-energy passive (e.g. PIT) or active (e.g. reverse GPS) tags can overcome these limitations, but instead require animals to remain within a bounded study area or to come into close proximity to detectors. C_LIO_LIHere we describe one solution that can overcome many current limitations by employing the massive global network of personal mobile phones as gateways for tracking animals using Bluetooth low energy (BLE) beacons. In areas with medium to high density of people, these simple-to-make beacons can provide regular updates of position over long time periods (battery life 1-3 years). We describe how to use off-the-shelf components to produce BLE beacons that weigh c. 5-6 g and cost < $7USD. Using field testing, we then show that beacons are capable of producing high-frequency tracking data that can be used to build home ranges or to detect spatio-temporal co-occurrences among individuals. C_LIO_LIBLE beacons are a low cost, low energy solution for studying organisms (e.g. birds, mammals, and reptiles) living and moving in urban landscapes. Their low weight and small size makes them particularly well-suited for tracking smaller species. When combined with fixed gateways, their use can also be extended to non-urban habitats. Their high accessibility is likely to make them an attractive solution for many research projects. C_LI

animal behavior and cognition↗

bioRxiv2024

Long-term stability of dominance hierarchies in a wild parrot with fission-fusion dynamics

Dominance hierarchies are a common feature of stable groups, allowing animals to limit the costs of fighting over access to resources. However, while the emergence of dominance is relatively well known from species that form stable groups, less is known about whether hierarchies are maintained in societies with open group membership. One challenge for species that live in an open social environment is that they have the possibility of engaging in dominance interactions with a large number of conspecifics. To better understand how animals navigate the complexities of interacting within a large, open society, we recorded social associations and aggressive interactions in a highly social, communally roosting parrot, the sulphur-crested cockatoo (Cacatua galerita). By following 515 individuals across three neighbouring communities and recording social interactions during foraging, we show that sulphur-crested cockatoos form clear, linear hierarchies. We find males rank higher than females and that adults rank higher than juveniles. Within sex, where individuals may still have to compete with up to 100 individuals from the same age-sex class, body size did not affect dominance rank. Finally, we find that, despite highly dynamic social associations (fission-fusion dynamics) among individuals, hierarchies are stable, with dominance ranks being highly repeatable across at least three years. This study demonstrates that closed group membership is not a pre-requisites for stable dominance hierarchies to emerge.

animal behavior and cognition↗

bioRxiv2023

Social decision-making in a wild parrot relies on both individual recognition and intrinsic markers

O_LIDominance hierarchies are generally thought to form over time via memory of repeated interactions. However, dominance hierarchies are also occasionally reported in species with fission-fusion social dynamics, where individuals may encounter large numbers of individuals, leading to incomplete social information. It it has been alternatively proposed that the complex decision-making required in these circumstances may lead to increased selection for social cognition and memory, or to the evolution of mixed strategies that rely on memory for interaction with familiars and status signals for strangers. C_LIO_LIHere, test these competing hypotheses by recording social associations and aggressive interactions in a highly social, large-brained parrot, the sulphur-crested cockatoo ( Cacatua galerita). We followed 411 individuals across three neighbouring roost sites, where individuals exhibit stable dominance hierarchies within roosts, alongside a high degree of fission-fusion dynamics within roosts and regular between-roost movements. C_LIO_LIWe found evidence that sulphur-crested cockatoos use a two-fold social strategy when initiating or reacting to an aggression. For familiar individuals, aggressions were initiated or escalated based on rank difference. When facing less familiar individuals, decisions to interact -- or escalate -- were based on the relative weight, with interactions directed towards, and more likely to escalate between, individuals of similar weight. C_LIO_LIOur results suggest that social knowledge remains an important determinant of aggressive interactions in highly fission-fusion systems, but that individuals can dynamically incorporate other potential cues of competitive ability when knowledge is lacking. C_LI

animal behavior and cognition↗

bioRxiv2022

Multi-network analysis reveals context-dependent kin relationships in wild sulphur-crested cockatoos, Cacatua galerita

O_LIA preference to associate with kin facilitates inclusive fitness benefits, and increased tolerance or cooperation between kin may be an added benefit of group living. Many species exhibit preferred associations with kin, however it is often hard to disentangle active preferences from passive overlap, for example caused by limited dispersal or inheritance of social position. C_LIO_LIMany parrots exhibit social systems consisting of pair-bonded individuals foraging in variably sized fission-fusion flocks within larger communal roosts of hundreds of individuals. Previous work has shown that, despite these fission-fusion dynamics, individuals can exhibit long-term preferred foraging associations outside their pair-bonds. Yet the underlying drivers of these social preferences remains largely unknown. C_LIO_LIIn this study, we use a network approach to examine the influence of kinship on social associations and interactions in wild, communally roosting sulphur-crested cockatoos, Cacatua galerita. We recorded roost co-membership, social associations and interactions in 561 individually marked birds across three neighbouring roosts. We then collected genetic samples from 205 cockatoos, and conducted a relationship analysis to construct a kinship network. Finally, we tested correlations between kinship and four social networks: association, affiliative, low-intensity aggression, and high-intensity aggression. C_LIO_LIOur result showed that while roosting groups were clearly defined, they showed little genetic differentiation or kin structuring. Between roost movement was high, with juveniles, especially females, repeatedly moving between roosts. Both within roosting communities, and when visiting different roosts, individuals preferentially associated with kin. Supporting this, individuals were also more likely to allopreen kin. However, contrary to expectation, individuals preferred to direct aggression towards kin, with this effect only observed when individuals shared roost membership. C_LIO_LIBy measuring social networks within and between large roosting groups, we could remove potential effects of passive spatial overlap on kin structuring. Our study reveals that sulphur-crested cockatoos actively prefer to associate with kin, both within and between roosting groups. By examining this across different interaction types, we further demonstrate that sulphur-crested cockatoos exhibit behavioural and context-dependent interaction rules towards kin. Our results help reveal the drivers of social association in this species, while adding to the evidence for social complexity in parrots. C_LI

animal behavior and cognition↗

bioRxiv2021

Costs dictate strategic investment in dominance interactions

Dominance is important for access to resources. As dominance interactions are costly, individuals should be strategic in who they interact with. One hypothesis is that individuals should direct costly interactions towards those closest in rank, as they have most to gain--in terms of attaining or maintaining dominance--from winning such interactions. Here, we show that male vulturine guineafowl (Acryllium vulturinum), a gregarious species with steep dominance hierarchies, strategically express higher-cost aggressive interactions towards males occupying ranks immediately below themselves in their groups hierarchy. In contrast, lower-cost aggressive interactions are expressed towards group members further down the hierarchy. By directly evaluating differences in the strategic use of higher- and lower-cost aggressive interactions towards competitors, we show that individuals disproportionately use highest-cost interactions--such as chases--towards males found one to three ranks below themselves. Our results support the hypothesis that the costs associated with different interaction types can determine their expression in social groups with steep dominance hierarchies.

animal behavior and cognition↗