Behavioral Correlations Associated with Fear of Humans Differ between Rural and Urban Burrowing Owls

Abstract

Behavioral studies are fundamental to understanding how animal populations face global change. Although much research has centered upon the idea that individuals can adaptively modify their behaviors to cope with environmental changes, recent evidence supports the existence of individual differences in suites of correlated behaviors. However, little is known about how selection can change these behavioral structures in populations subject to different environmental constraints. The colonization of urban environments by birds has been related to their inter-individual variability in their fear of humans, measured as their flight initiation distance to an approaching human, such that urban life would select for fearless individuals. This behavior has been demonstrated to be heritable and highly consistent throughout the adult lifespan of burrowing owls (Athene cunicularia). Here, we experimentally assessed, in field conditions, whether urban life involves changes in other behaviors such as exploration and antipredatory response through their correlation with fear of humans. Breeding urban birds were more fearless toward humans and were quicker to explore a new food resource and defend their nests from predators than their rural counterparts. However, while fear of humans positively correlated with exploration and antipredatory response in the rural population, it only correlated with exploration in the urban one. Predator release in urban environments could relax-and even counterselect-antipredator behaviors, thus dismantling the behavioral correlation existent in natural populations. Altogether, our results suggest that rural and urban animals may differ in some behavioral aspects, may be as a consequence of the selection processes acting during the colonization of urban areas as well as the different ecological environments encountered by individuals.

Great tits take greater risk toward humans and sparrowhawks in urban habitats than in forests

“…Thus, it is important to look at behavioral variation on multiple levels (Dingemanse et al, ). Third, the contrast between our results and other recent studies addressing the relationship between responses to humans and to non‐human predators (Carrete & Tella, ; Myers & Hyman, ) suggests that estimating the same trait (e.g., risk‐taking) from different forms of behavior (e.g., aggression vs. avoidance) might yield different results. Therefore, comprehensive studies investigating several behavioral domains at the same time along the urbanization gradient will be important for furthering our understanding of urban adaptations.…”

“…These two studies notably differ from ours in that they assessed responses to humans through avoidance behavior (flight initiation distances) and responses to non‐human predators through aggression (mobbing), whereas we assessed both behaviors through avoidance (i.e., delaying return to the nest box where the threat appeared). Interestingly, both earlier studies found that behaviors within the same domain (i.e., avoidance vs. aggression) remained correlated even in urban birds: There was a habitat‐independent correlation between avoidance of humans and avoidance of novel objects (Carrete & Tella, ), as well as between aggression toward predators and aggression toward conspecifics (Myers & Hyman, ). Despite focusing on a single domain, however, we found no phenotypic correlation in the risk‐taking in great tits.…”

“…Humans in cities seldom pose direct threat to free‐living animals like birds (Clucas & Marzluff, ); thus, greater risk‐taking (e.g., reduced avoidance) toward humans can be advantageous in urban habitats. Reduced flight responses have been observed in many urban animals (Samia, Nakagawa, Nomura, Rangel, & Blumstein, ), including birds (Carrete & Tella, ; Møller et al, ; Myers & Hyman, ; Vincze et al, ), mammals (McCleery, ; Uchida, Suzuki, Shimamoto, Yanagawa, & Koizumi, ), and reptiles (Lapiedra, Chejanovski, & Kolbe, ; McGowan, Patel, Stroh, & Blumstein, ).…”

“…Risk‐taking toward humans is often suggested to correlate with other forms of risk‐taking behavior, such as aggressiveness (risk‐taking toward a conspecific opponent; Scales, Hyman, & Hughes, ; Myers & Hyman, ), neophobia and exploration (risk‐taking toward novel stimuli; Bókony, Kulcsár, Tóth, & Liker, ; Carrete & Tella, ), and anti‐predator behavior (risk‐taking toward non‐human predators; Bókony et al, ; Carrete & Tella, ; Myers & Hyman, ). Such phenotypic correlation across different situations is often called “behavioral syndrome” (Sih, Bell, & Johnson, ; Herczeg & Garamszegi, ; but see Dingemanse, Dochtermann, & Nakagawa, ).…”

Urban Great Tits (Parus major) Show Higher Distress Calling and Pecking Rates than Rural Birds across Europe

“…This finding is in line with studies showing that urban great tits are more explorative and less neophobic than their rural counterparts (Tryjanowski et al, 2016;Charmantier et al, 2017;Riyahi et al, 2017), and display shorter flight initiation distances (Møller, 2008(Møller, , 2012, which represent other aspects of the proactive coping strategy. Findings on the great tit are also in line with data from other bird species, for which urban populations have also been found to display proactive behaviors (Evans et al, 2010;Carrete and Tella, 2017), but these studies compared few populations (Miranda et al, 2013). Our study included 14 populations from a large geographic area and revealed consistent results across localities, allowing to generalize the impact of urbanization on great tit coping styles.…”