Repeatability and degree of territorial aggression differs among urban and rural great tits (Parus major)

Abstract

Animals in urban habitats face many novel selection pressures such as increased human population densities and human disturbance. This is predicted to favour bolder and more aggressive individuals together with greater flexibility in behaviour. Previous work has focussed primarily on studying these traits in captive birds and has shown increased aggression and reduced consistency between traits (behavioural syndromes) in birds from urban populations. However, personality (consistency within a behavioural trait) has not been well studied in the wild. Here we tested whether urban free-living male great tits show greater territorial aggression than rural counterparts. We also tested predictions that both behavioural syndromes and personality would show lower consistency in urban populations. We found that urban populations were more aggressive than rural populations and urban birds appeared to show lower levels of individual behavioural repeatability (personality) as predicted. However, we found no effect of urbanisation on behavioural syndromes (correlations between multiple behavioural traits). Our results indicate that urban environments may favour individuals which exhibit increased territorial aggression and greater within-trait flexibility which may be essential to success in holding urban territories. Determining how urban environments impact key fitness traits will be important in predicting how animals cope with ongoing urbanisation.

Of city and village mice: behavioural adjustments of striped field mice to urban environments

“…Similarly, previous studies reported more variation in the expression of measured behavioural responses in urban individuals compared to rural ones (e.g. 22 , 84 , 101 ). For example, Lehrer et al 101 found increased variance of vigilance behaviour in woodchucks ( Marmota monax ) along the rural–urban gradient.…”

“…Findings are consistent with previous literature on birds and larger mammals, suggesting an ubiquitous response to human-altered environments across taxa. Urbanisation may therefore act as a selective force driving the evolution of behavioural and phenotypic differences between urban and rural populations 22 . Cities provide a natural laboratory for understanding which role human activity plays in the reciprocal interactions between ecological and evolutionary processes, since the accelerated rates and increased magnitude of landscape-level changes mark them as hotspots of contemporary evolution 110,112 .…”

“… 20 , 21 ). “If some personality types are better suited to dealing with certain challenges than others, personality could determine how successfully individuals are able to occupy a range of different environments with different selective pressures” 22 . Following this line of reasoning, individual differences in spatial exploration/dispersal tendencies, risk-taking and tolerance to human disturbance might promote the successful colonisation and settlement in urbanised habitats of only certain behavioural types (e.g.…”

“…In the past few years, studies investigating behavioural adaptations to urban environments have flourished, focusing particularly on avian species (e.g. 22 , 63 – 65 ).…”

Nocturnal resting behaviour in urban great tits and its relation to anthropogenic disturbance and microclimate

“…Phenotype-matching habitat choice has been suggested as an explanation for settlement patterns in relation to human disturbance in dunnocks, Prunella modularis (Holtmann et al 2017). Moreover, it has been found that urban great tits differ in consistent behavioural traits from their rural conspecifics (Hardman and Dalesman 2018). It might well be that nonrandom distributions of great tit phenotypes also occur at smaller spatial scales within cities, such that individuals that are less sensitive to nocturnal disturbance are more likely to settle in disturbed areas.…”