Biology subjects

Firth, J. A.

Publications and source records attributed to Firth, J. A..

18 recordsLinked to original sources

bioRxiv2026

Wild great tits show social resilience in response to partner loss

Social relationships are foundational to animal societies, but individual social connections differ hugely in importance and strength. Key relationships, such as those between breeding partners, may be prioritised and more highly invested in by individuals, but a key question is the extent to which social flexibility allows individuals to respond to the loss of these key social relationships. Here, we use a detailed longitudinal dataset of individual breeding and social behaviour in wild great tits (Parus major) to characterise flexibility in social behaviour after the loss of their breeding partner ('widowing'). We show transient increases in two measures of sociality following the widowing event. Individuals' relationships with their replacement partner were initially weaker than those between non-widowed birds, but converged by the breeding season. Hence, we show that birds are robust to the loss of key social relationships and that great tits show a flexible ability to return to social equilibrium. Strong social resilience has implications for the response of populations to change and loss.

animal behavior and cognition↗

bioRxiv2026

Local density shapes complete brood failure across species boundaries in two sympatric songbirds

Reproduction in species with parental care involves sustaining a brood of offspring through an energetically demanding period, when shifts in resource availability, weather, predation risk, and parental condition can strongly alter offspring survival. The most extreme outcome is complete brood failure (death of all offspring), which is relatively frequent in many bird species and may occur when conditions cross a viability threshold. Although complete brood failure is important for shaping fitness variation and population dynamics, we have limited understanding of how intra- and interspecific density dependence governs these events, or of how factors such as habitat quality and disease burden contribute to them, because deriving this requires fine-scale, individual-level data collected across generations for multiple overlapping species. Using a dataset totalling 38,509 nesting attempts from great tits (Parus major) and blue tits (Cyanistes caeruleus) in Wytham Woods, Oxford, UK, we examined how brood failure is shaped by local conspecific and heterospecific density, habitat structure, and avian malaria infection for a subset. Complete brood failure was frequent (14.75%), mostly involving chick mortality in the nest consistent with starvation, rather than brood removal by predators. Relationships between density and brood failure were strong but species-specific. Specifically, great tit failure risk was higher in neighbourhoods that remained densely populated across years, whereas blue tit failure risk was lower where annual great tit or combined density was high, but not where annual blue tit density itself was high. This suggests that local overall density reflects continuing constraint for great tits, while local annual density may partly track favourable within-year conditions and settlement patterns for blue tits. In great tits, failure was also more common where oak density was low and farther from the closest river (Thames), while habitat associations were weak in blue tits. Malaria infection was spatially heterogeneous and covaried with density and habitat, but infection status did not significantly explain complete brood failure. Together, these results show that complete brood failure is shaped by spatially structured local ecological context, and how density dependence in these events can differ in direction and timescale between sympatric species.

ecology↗

bioRxiv2026

The Friendship Paradox across animal social systems is governed by network structure and biological features

A populations social structure, often represented as a social network, shapes fundamental biological processes including the spread of disease, information, and behaviour. The Friendship Paradox is a network phenomenon whereby the average individual has fewer friends than their friends do. This effect can be quantified as relationship disparity (the difference between an individuals connectedness and those they are connected to) which captures the local social environment. Previous work has shown that such relationship disparity can be exploited in effective outbreak monitoring, targeted health interventions and optimized contact tracing. Yet, how its magnitude varies across real-world social networks remains poorly understood. Here, we analyse relationship disparity across 391 empirical animal social networks to test how intrinsic network properties and biological attributes predict its extent. We find that smaller and sparser networks exhibit stronger relationship disparity, and it is further shaped by both species-specific differences and shared phylogenetic history. After controlling for variation in individual sociability, relationship disparity was more strongly accentuated in mammalian direct physical contact networks than indirect social association networks, whilst the corresponding finding was not detected among Sauropsids. Phylogenetic and species identity largely explained variation in relationship disparity indicating biological drivers. Together, these findings demonstrate that both network structure and biological attributes shape relationship disparity in animal social systems, providing a foundation for predicting how higher-order network architecture influences social processes such as contagion. Significance StatementIn natural populations, social connections are unevenly distributed, often resulting in a small subset of individuals that are highly connected while many are relatively peripheral. The Friendship Paradox is a measure of relationship disparity between individuals and their local social environment. Understanding how features of the social network and biological system are associated with relationship disparity can contribute to understanding what shapes social behaviour. Relationship disparity may not just be an emergent network property but could reflect a higher level of social structuring, and therefore shape processes that depend on social contacts. Our findings demonstrate the value of comparative network analysis for generating insights into fundamental principles structuring real-world societies.

animal behavior and cognition↗

bioRxiv2025

Social connections, group size and fine-scale manipulations of social stability shape learning, scrounging and foraging rate in wild great tits

The social environment provides both opportunities and challenges for foragers. How multiple components of sociality and foraging interact simultaneously is poorly understood, while experimental manipulation of sociality within wild foraging groups is rare. We tested whether production learning, scrounging, and foraging rate are associated with individual social network metrics and manipulated social stability in mixed species flocks of wild birds. First, individuals were randomly allowed access to, and learned to forage primarily from, one of five feeders. Thereafter, we performed two reversals, manipulating social connections by either assigning birds to a new feeder along with all others assigned to their previous feeder (stable treatment) or reassigning each bird individually (unstable treatment). Most of the effects observed were context dependent but in general we found that: i) Learning was slower in the stable treatment, for individuals with higher weighted degree, and in smaller flocks; ii) Scrounging was higher in the stable treatment, increased with weighted degree, but decreased with flock size; and iii) Foraging rate was predicted only by weighted degree. Our findings demonstrate the complex and dynamic nature of the relationship between sociality and foraging and suggest that selection for group living is more nuanced than usually recognized.

animal behavior and cognition↗

bioRxiv2025

Support for the social buffering hypothesis, especially under unpredictable precipitation regimes

Sociality is hypothesised to buffer populations against environmental stochasticity by stabilising key vital rates, yet this has rarely been tested across diverse taxa. We compiled demographic time series from 87 populations for 66 animal species spanning 12 taxonomic classes to test whether sociality promotes demographic buffering and whether this relationship depends on environmental context. Using stochastic elasticities and phylogenetically comparative analyses, we find broad support for the social buffering hypothesis: more social species exhibit lower sensitivity of population growth to vital rate variance (lower stochastic elasticity to vital rate variances, |T{sigma}|), particularly in juvenile survival and reproduction. Contrary to expectations, juvenile vital rates, but not adult survival, showed the strongest buffering patterns in social taxa, suggesting life-stage-specific social mechanisms. Furthermore, we show that social species invest more in maximising the average performance of adult survival and reproduction (higher stochastic elasticity to vital rate means, T), consistent with adaptive strategies favouring canalisation of fitness-related traits. This buffering benefit is especially relevant in highly unpredictable environments: in climates with erratic precipitation, social species have greater demographic advantages, exhibiting even lower T{sigma} values. Together, these findings provide support for the social buffering hypothesis, especially in highly stochastic environments. Social traits confer some demographic stability under moderate climatic conditions, but may become more relevant under extreme stochasticity--an insight particularly important for understanding population resilience in a rapidly changing world.

animal behavior and cognition↗

bioRxiv2024

Timing and social consequences of divorce in wild great tits: a phenomenological approach

3Social behaviour is a key part of life for many species. In monogamously breeding species, social associations between breeding partners are particularly important. Selection of a breeding partner often begins well before reproduction, and this process can affect subsequent reproductive success. Thus, the non-breeding season can shape behaviour during the breeding season. However, it is currently unknown how breeding season outcomes can impact associate choice during the non-breeding season, as studying this requires high volumes of cross-context individual social data. This study used three years of wild great tit social data from Wytham Woods, Oxford, UK, to examine social associations between pairs classified with respect to prior and future breeding status (divorcing, faithful, new and juvenile). We found distinct patterns of social association in divorcing pairs from early winter, suggesting that divorce is an ongoing behavioural process. Newly forming pairs initially associated similarly to divorcing pairs, but became similar to faithful pairs over time. On a finer spatiotemporal scale, the behaviour of faithful and divorcing birds diverged over the winter. These results provide the first evidence of a behavioural signature of divorce during the non-breeding season in great tits, while suggesting that different behaviours may drive behavioural divorce at different times.

animal behavior and cognition↗

bioRxiv2024

Density-dependent network structuring within and across wild animal systems

High population density should drive individuals to more frequently share space and interact, producing better-connected spatial and social networks [1-4]. Although this theory is fundamental to our understanding of disease dynamics [2,5-8], it remains unconfirmed how local density generally drives individuals positions within their networks, which reduces our ability to understand and predict density-dependent processes [4,9,10]. Here we provide the first general evidence that density drives greater network connectedness at fine spatiotemporal scales, at the scale of individuals within wild animal populations. We analysed 36 datasets of simultaneous spatial and social behaviour in >58,000 individual animals, spanning 30 species of fish, reptiles, birds, mammals, and insects. 80% of systems exhibited strong positive relationships between local density and network centrality. However, >80% of relationships were nonlinear and 75% became shallower at higher values, signifying that demographic and behavioural processes counteract densitys effects, thereby producing saturating trends [11-15]. Densitys effect was much stronger and less saturating for spatial than social networks, such that individuals become disproportionately spatially connected rather than socially at higher densities. Consequently, ecological processes that depend on spatial connections (e.g. indirect pathogen transmission, resource competition, and territory formation) are likely more density-dependent than those involving social interactions (e.g. direct pathogen transmission, aggression, and social learning). These findings reveal fundamental ecological rules governing societal structuring, with widespread implications. Identifying scaling rules based on processes that generalise across systems, such as these patterns of density dependence, might provide the ability to predict network structures in novel systems.

ecology↗

bioRxiv2024

Continent-wide drivers of spatial synchrony in age structure across wild great tit populations

Spatio-temporal variation in age structure influences population dynamics, yet we have limited understanding of the spatial scale at which its fluctuations are synchronised between populations. Using 32 great tit populations, spanning 3200km and >130,000 birds across 67 years, we quantify spatial synchrony in breeding age structure and its drivers. We show that larger clutch sizes, colder winters and summers, and larger beech crops lead to younger populations. We report distant-dependent spatial synchrony of age structure, which is maintained at approximately 650km. Despite covariation with age structure, reproductive and environmental variables do not influence the scale of synchrony, except for a moderate effect of beech masting. We suggest that local ecological and density-dependent dynamics impact how environmental variation interacts with age structure, influencing estimates of the environments effect on spatial synchrony. Our analyses demonstrate the operation of synchrony in age structure over large scales, with implications for age-dependent demography in populations.

ecology↗

bioRxiv2024

Age-specificity in territory quality and spatial structure in a wild bird population

Age influences behaviour, survival, and reproduction; hence variation in population age structure can affect population-level processes. The extent of spatial age structure may be important in driving spatially-variable demography, particularly when space-use is linked to reproduction, yet it is not well understood. We use long-term data from a wild bird population to examine spatial age structure and quantify covariance between territory quality and age. We find associations between age and aspects of territory quality, but little evidence for spatial age structure compared to territory quality and reproductive structure. We also report little between-year repeatability of spatial age structure compared to structure in reproductive output. We suggest that high breeding site fidelity and frequent territory turnover by younger breeders, driven by high mortality and immigration rates, limits the association between age and territory quality and weakens overall spatial age structure. Greater spatial structure and repeatability in reproductive output compared to age suggests that habitat quality may be more important in driving spatially-variable demography than age in this system. We suggest that the framework developed here can be used in other taxa to assess spatial age structure, particularly in longer-lived species where we predict from our findings there may be greater structure.

ecology↗

bioRxiv2024

Environmental similarity between relatives reduces heritability of reproductive timing in wild great tits

Intraspecific variation is necessary for evolutionary change and population resilience, but the extent to which it contributes to either depends on the causes of this variation. Understanding the causes of individual variation in traits involved with reproductive timing is important in the face of environmental change, especially in systems where reproduction must coincide with seasonal resource availability. However, separating the genetic and environmental causes of variation is not straightforward, and there has been limited consideration of how small-scale environmental effects might lead to similarities between individuals that occupy similar environments, potentially biasing estimates of genetic heritability. In ecological systems, environments can often be complex in their spatial structure, and it may therefore be important to account for similarities in the environments experienced by individuals within a population beyond considering spatial distances alone. Here, we construct multi-matrix quantitative genetic animal models using over 11,000 breeding records (spanning 35 generations) of individually-marked great tits (Parus major) and information about breeding proximity and habitat characteristics to quantify the drivers of variability in two key seasonal reproductive timing traits. We show that the environment experienced by related individuals explains around a fifth of the variation seen in reproductive timing, and accounting for this leads to decreased estimates of heritability. Our results thus demonstrate that environmental sharing between relatives can strongly affect estimates of heritability and therefore alter our expectations of the evolutionary response to selection.

evolutionary biology↗

bioRxiv2024

Different types of social links contrastingly shape reproductive wellbeing in a multi-level society of wild songbirds

The social environment has diverse consequences for individuals welfare, health, reproductive success, and survival. This environment consists of different kinds of dyadic bonds that exist at different levels; in many social species, smaller social units come together in larger groups, creating multilevel societies. In great tits (Parus major), individuals have four major types of dyadic bonds: pair mates, breeding neighbours, flockmates, and spatial associates, all of which have been previously linked to fitness outcomes. Here, we show that these different types of dyadic bonds are differentially linked with subsequent reproductive success metrics in this wild population and that considering spatial effects provides further insights into these relationships. We provide evidence that more social individuals had a higher number of fledglings, and individuals with more spatial associates had smaller clutch sizes. We also show individuals with stronger bonds with their pair mate had earlier lay dates. Our study highlights the importance of considering different types of dyadic relationships when investigating the relationship between wellbeing and sociality, and the need for future work aimed at experimentally testing these relationships, particularly in spatially structured populations.

ecology↗

bioRxiv2023

Unravelling effects of fine-scale changes within wild-bird flocks on sociality

O_LISocial structure and individual sociality impact a wide variety of behavioural and ecological processes. Although it is well known that changes in the physical and social environment shape sociality, how perturbations govern sociality at a fine spatial scale remains poorly understood. By applying automated experimental treatments to RFID-tracked wild great tits (Parus major) in a field experiment, we examined how individual social network metrics changed when food resources and social stability were experimentally manipulated at the within-group spatial scale. C_LIO_LIFirst, we examined how individual sociality responds when food resources changed from a dispersed distribution (50m apart) to a clustered distribution (1m apart). Second, we tested how sociality changed when individuals were restricted to feeding in a manner that mimics assortative behaviour within flocks. Third, we tested the effects of experimentally manipulating the stability of these social groupings. Finally, we returned the feeders to the original dispersed distribution to test whether effects carried over. C_LIO_LIRepeatability analyses showed consistent differences among individuals in their social phenotypes across the various manipulations; dyadic association preferences also showed consistency. Nevertheless, average flock size and social centrality measures increased after the food was clustered. Some of these metrics changed further when birds were then forced to feed from only one of the five clustered feeders. There was some support for group stability at individual feeders also impacting individual social network metrics: increase in flock size was more pronounced in the stable than the unstable group. Most of the differences in sociality were maintained when the food distribution returned to the dispersed pattern, and this was caused primarily by the change in resource distribution rather than the social manipulation. C_LIO_LIOur results show that perturbations in the access to resources and social group stability can change sociality at a surprisingly fine spatial scale. These small-scale changes could arise through a variety of mechanisms, including assortative positioning within groups due to, for instance, similarity among individuals in their preferences for different resource patches. Our results suggest that small-scale effects could lead to social processes at larger scales and yet are typically overlooked in social groups. C_LI

animal behavior and cognition↗

bioRxiv2023

Social network centrality predicts dietary decisions in a wild bird population

How individuals balance costs and benefits of group living remains central to understanding sociality. In relation to diet, social foraging provides many advantages but also increases competition. Nevertheless, social individuals may offset increased competition by broadening their diet and consuming novel foods. Despite the expected relationships between social behaviour and dietary decisions, how sociality shapes individuals novel food consumption remains largely untested in natural populations. Here, we use wild, RFID-tracked, great tits to experimentally test how sociality predicts dietary decisions. We show that individuals with more social connections have higher propensity to use novel foods compared to socially-peripheral individuals, and this is unrelated to neophobia, observations, and demographic factors. These findings indicate sociable individuals may offset potential costs of competition by foraging more broadly. We discuss how social environments may drive behavioural change in natural populations, and the implications for the causes and consequences of social strategies and dietary decisions.

ecology↗

bioRxiv2022

Different helminth parasites show contrasting relationships with age in a wild ungulate

As animals age they often exhibit substantial physiological and behavioural changes that can drive changes in infection status over the lifespan. Generally, immunosenescence is expected to lead to greater infection in older individuals, but this process could be confounded or counteracted by changes in behaviour, selective disappearance of certain individuals, or a range of immune processes. Here, we uncover contrasting age-related patterns of infection across three different helminth parasites in wild adult red deer (Cervus elaphus). Counts of strongyle nematodes (order: Strongylida) increased with age, while counts of liver fluke (Fasciola hepatica) and tissue worm (Elaphostrongylus cervi) decreased. These relationships could not be explained by selective disappearance of certain individuals or changes in behaviour, suggesting that immune changes could be responsible. Additionally, we found a positive relationship between social connectedness and strongyle infection, implying that previously documented age-related decreases in social behaviour may minimise exposure, reducing the negative effects of immunosenescence. These findings demonstrate that burdens of different parasites can show contrasting changes over an individuals lifespan depending on a complex suite of intrinsic and extrinsic factors.

ecology↗

bioRxiv2022

Social learning mechanisms shape transmission pathways through replicate great tit social networks

The emergence and spread of novel behaviours via social learning can lead to rapid population-level changes whereby the social connections between individuals shape information flow. However, behaviours can spread via different mechanisms and little is known about how information flow depends on the underlying learning rule individuals employ. Here, comparing four different learning mechanisms, we simulated behavioural spread on replicate empirical social networks of wild great tits and explored the relationship between individual sociality and the order of behavioural acquisition. Our results reveal that, for learning rules dependent on the sum and strength of social connections to informed individuals, social connectivity was related to the order of acquisition, with individuals with increased social connectivity and reduced social clustering adopting new behaviours faster. However, when behavioural adoption depends on the ratio of an individuals social connections to informed versus uninformed individuals, social connectivity was not related to the order of acquisition. Finally, we show how specific learning mechanisms may limit behavioural spread within networks. These findings have important implications for understanding whether and how behaviours are likely to spread across social systems, the relationship between individuals sociality and behavioural acquisition, and therefore for the costs and benefits of sociality.

animal behavior and cognition↗

bioRxiv2021

Ageing red deer alter their spatial behaviour and become less social

Social relationships are important to many aspects of animals lives, and an individuals connections may change over the course of their lifespan. Currently, it is unclear whether social connectedness declines within individuals as they age, and what the underlying mechanisms might be, so the role of age in structuring animal social systems remains unresolved, particularly in non-primates. Here, we describe senescent declines in social connectedness using 43 years of data in a wild, individually monitored population of a long-lived mammal (European red deer, Cervus elaphus). Applying a series of spatial and social network analyses, we demonstrate that these declines occur due to within-individual changes in social behaviour, with correlated changes in spatial behaviour (smaller home ranges and movements to lower-density, lower-quality areas). These findings demonstrate that within-individual socio-spatial behavioural changes can lead older animals in fission-fusion societies to become less socially connected, shedding light on the ecological and evolutionary processes structuring wild animal populations.

ecology↗

bioRxiv2020

Spatial point locations explain a range of social network positions in a wild ungulate

The structure of wild animal social systems depends on a complex combination of intrinsic and extrinsic drivers. Population structuring and spatial behaviour are key determinants of individuals observed social behaviour, but quantifying these spatial components alongside multiple other drivers remains difficult due to data scarcity and analytical complexity. We used a 43-year dataset detailing a wild red deer population to investigate how individuals spatial behaviours drive social network positioning, while simultaneously assessing other potential contributing factors. Using Integrated Nested Laplace Approximation (INLA) multi-matrix animal models, we demonstrate that social network positions are shaped by two-dimensional landscape locations, pairwise space sharing, individual range size, and spatial and temporal variation in population density, alongside smaller but detectable impacts of a selection of individual-level phenotypic traits. These results indicate strong, multifaceted spatiotemporal structuring in this society, emphasising the importance of considering multiple spatial components when investigating the causes and consequences of sociality. Authorship StatementGFA conceived the study, analysed the data, and wrote the manuscript, advised by JAF. AM and SM collected the data. JAF, JMP, THCB, and DN commented on the manuscript. Data Accessibility StatementThe code used here is available at https://github.com/gfalbery/Spocial_Deer. On acceptance, the data will be uploaded to the same repo, which will be archived on Zenodo.

ecology↗

bioRxiv2018

Movement and conformity interact to establish local behavioural traditions in animal populations

The social transmission of information is critical to the emergence of animal culture. Two processes are predicted to play key roles in how socially-transmitted information spreads in animal populations: the movement of individuals across the landscape and conformist social learning. We develop a model that, for the first time, explicitly integrates these processes to investigate their impacts on the spread of behavioural preferences. Our results reveal a strong interplay between movement and conformity for determining whether local traditions establish across a landscape or whether a single preference dominates the whole population. The model is able to replicate a real-world cultural diffusion experiment in great tits Parus major, but also allows for a range of predictions for the emergence of animal culture under various initial conditions, habitat structure and strength of conformist bias to be made. Integrating social behaviour with ecological variation will be important for understanding the stability and diversity of culture in animals.

animal behavior and cognition↗