Patterns of association at feeder stations for Common Pheasants released into the wild: sexual segregation by space and time

Abstract

Sexual segregation is common and can occur when sexes occupy different habitats, and/ or when sexes aggregate assortatively within the same habitats. However, it is rarely studied in birds, with most previous work concentrating on differential settlement by the sexes in discrete habitats, often separated by large distances. Little attention has been paid to patterns of segregation within the same site. We reared 200 Common Pheasants Phasianus colchicus and released them onto a relatively small site of 250 ha and recorded their patterns of association and differential use of artificial feeders in space and time. Particular feeders were preferred by one sex, although we found no features of the local habitat which explained such preferences. Furthermore, we found sex differences in the use of feeders throughout the day, with females preferentially visiting them in the morning and the proportion of females visiting feeders increasing as the year progressed. Social network analyses found that in the first month after release into the wild, females did not associate strongly with other females, which was surprising as, prior to release, females have been shown to associate with other females in both semi-natural conditions and when tested in isolation. However, sexual segregation was clearly seen after 1 month of being released and became more pronounced as the year progressed. Females associated with other females from November to February, whereas males avoided other males over this same period. Sexes became less likely to associate with one another in 5 of the 6 months monitored. Such avoidance observed in males suggests that they start to form territories much sooner than previously thought. Pheasants exhibit clear patterns of finescale sexual segregation based on space and time, which was observed in their social preferences at feeding sites. Such detailed fine-scale segregation is rarely observed in birds.

Peer Review #3 of "The relationship between social rank and spatial learning in pheasants, Phasianus colchicus: cause or consequence? (v0.1)"

“…Learning allows individuals to adapt to changing (social) environments. Performances on operant foraging (starlings, Sturnus vulgaris, Boogert, Reader, & Laland, 2006) and spatial learning tasks are reported as superior in dominant individuals (pheasants, Phasianus colchicus, Langley et al 2018; mountain chickadees, Poecile gambeli, Pravosudov et al 2003;mice, Fitchett et al 2005;Francia et al 2006). This may be because individuals that are inherently good at learning are more efficient at beneficial behaviours such as foraging (bumblebees, Bombus terrestris, Raine & Chittka, 2008), mate choice (Dukas & Ratcliffe, 2009), and navigating the social environment which brings fitness benefits.…”

“…Manuscript to be reviewed Whiteside et al, 2018) and territory holders have smaller, more concentrated home ranges than subordinate satellite males (Grahn, Goransson, & von Schantz, 1993). Male pheasants exhibit behavioural indicators of dominance, such as crowing (Ridley & Hill 1987;Heinz & Gysel, 1970) and lateral displays (Hill and Robertson 1988), and captive studies demonstrate that dominant males perform these dominance display behaviours at a significantly higher rate than subordinates (Mateos & Carranza, 1999).…”

“…It is unclear whether captive social hierarchies reflect what occurs in the wild. We have previously shown that variation in performance on a spatial discrimination task is associated with social rank in adult male pheasants, which were tested while housed in a group with an established social hierarchy (Langley et al 2018). Perhaps, male pheasants that are inherently good at learning about space become dominant because they are better able to recall spatial features and so more efficiently establish and hold a territory.…”

No evidence that footedness in pheasants influences cognitive performance in tasks assessing colour discrimination and spatial ability

“…Therefore, laterality may benefit one task more than another. Critically, for studies of lateralization, pheasants are Galliformes, like chickens, a well-studied model system for laterality in birds (e.g., Rogers et al, 2004;Tommasi & Vallortigara, 1999); they have lateral placed eyes; they eat both live prey and mixed grain (Hill & Robertson, 1988); and they live in groups (Ridley & Hill, 1987;Whiteside, van Horik, Langley, Beardsworth, Capstick, & Madden, 2018). These factors suggest that an asymmetrical brain could offer survival advantages: detecting predators; selecting nutritious food items; and coordinating group actions, respectively.…”

Peer Review #3 of "Size dimorphism and sexual segregation in pheasants: tests of three competing hypotheses (v0.1)"

“…Firstly, pheasants are at risk from terrestrial predators, such as the fox, Vulpes vulpes 154 (Hessler et al 1970; Krauss et al 1987), and aerial predators, such as goshawks, Accipter 155 gentilis, sparrow hawks, Accipiter nicus, and buzzards, Buteo buteo, (Kenward et al 2001; 156 Kenward et al 1981) resulting in high mortality rates of up to 80% in the first month after 157 release into the wild (Hessler et al 1970). Such predation risk is unlikely to explain segregation 158 due to risk aversion by females caring for young because segregation occurs prior to the first 159 breeding season Whiteside et al 2018). However, outside the breeding 160 season, males may still opt for a riskier foraging and movement strategy if there is a benefit for 161 their growth.…”