Social bonds in a flock bird: Species differences and seasonality in social structure in captive flamingo flocks over a 12-month period

Abstract

Social network analysis (SNA) is a popular tool for investigating key components of sociality in free-living populations, and is growing in its application to captive animal systems. For social species held in captivity, welfare may be improved if protocols for care take key aspects of sociality into account. Individuals may benefit from investment in social affiliations and these relationships may exist over many years. Here we examine patterns of association that exist within captive flamingo (Phoenicopteridae) flocks across a 12-month period. We test the hypotheses that birds will show stable bonds with specific individuals within a flock, and that these bonds will be stable over time. Flamingos are well known for being highly-gregarious birds yet the importance of specific relationships between birds in a flock is still poorly defined. Four flocks of captive flamingos, of five species were included in the study at WWT Slimbridge Wetland Centre to assess the strength and consistency of bonds between individuals. Social associations were scored for all flocks from March 2012 to March 2013, with an average of 98days/sample time/flock. Each flock showed evidence of specific preferential associations between birds, which, in some cases, remained constant over the period of observations. Networks highlight the existence of inter- and intrasexual bonds present in all flamingo flocks. Mantel tests determine that strong dyadic bonds are maintained in (spring/summer) and out (autumn/winter) of the breeding season. Measuring social behaviour may provide an insight into flamingo welfare as changes in the number of associates and mean time spent associating appears to be impacted upon by environmental variables, such as enclosure type. As consistent partnerships are maintained between birds (of all flocks of all species) across season, there are potential implications for breeding and mate selection if new partnerships are not being formed at breeding times.