Is group familiarity important in conservation translocations?

Abstract

Translocations can create an abrupt transition to an unknown environment. Learning by observing others (social learning) may be an important way that naïve animals can adapt their behaviour quickly and survive the post-release period, particularly when peers are familiar [1]. However, little is known about how social bonds are maintained or disrupted during translocations, or if altered social dynamics have consequences for population stability [2] and the success of our conservation actions. Establishing new populations (or supplementing pre-existing ones) by moving groups of juveniles is a main focus of conservation for hihi (Notiomystis cincta), a threatened New Zealand passerine. Juvenile hihi form social groups post-independence from their parents (see image), and these social relationships alter their ability to discover new food sources in situ. We used a recent translocation to test how movement changes social bonds. We collected data on associations (i) pre-translocation, (ii) in temporary captivity during translocation, and (iii) following release to track how social bonds change during translocations. Associations were recorded pre-translocation and post-release by observing individually colour-ringed hihi, to determine which birds were repeatedly seen together in the same locations at the same time. During temporary captivity, we used video recordings to document behaviour. Furthermore, during the temporary captivity stage we established aviaries of familiar and un-familiar hihi from within the source population to assess if translocating coherent groups maintained social bonds. We discuss the consequences of maintaining and disrupting social bonds for social learning (food finding) and survival rates post-release. Despite a growing awareness that the characteristics of social networks can have consequences for the rapid spread of behavioural change, social associations are rarely accounted for in conservation translocation events. However, this could be an important consideration when animals often change behaviour as a first-response mechanism to survive in new environments.

Image: Sketch of three juvenile hihi sitting together on a branch, the typical social behaviour seen in groups.

[1] Swaney, W., Kendal, J., Capon, H., Brown, C., & Laland, K. N. (2001). Familiarity facilitates social learning of foraging behaviour in the guppy. Animal Behaviour, 62(3), 591-598.

[2] Kurvers, R. H. J. M., Krause, J., Croft, D. P., Wilson, A. D. M., & Wolf, M. (2014). The evolutionary and ecological consequences of animal social networks: emerging issues. Trends in Ecology & Evolution, 29(6), 326-35.