Will they tern up? Socially attracting black-fronted terns to braided river colonies sites

Abstract

Black-fronted terns (Chlidonias albostriatus) are an endemic bird species that rely on New Zealand’s braided river ecosystems for breeding. Black-fronted terns have a small, declining population and are globally endangered, primarily due to predation. Effective black-fronted tern management is challenging, due to the dynamic and unpredictable nature of the braided river environment as well as the behaviour of the terns themselves. Black-fronted terns frequently change their breeding colony locations both within and between years. The ability to attract prospecting terns to a particular breeding site would allow for increased planned protection for colonies. Social attractants, decoys and audio playback, were deployed at ten sites within nine Canterbury braided rivers in the 2016 breeding season. We found that the terns interacted significantly more (P < 0.001) with the social attractants compared to the control plots (social attractants absent). Nearest tern breeding sites were recorded for eight of the ten sites, with five of these nesting records occurring within 300 m of the experimental plots. These results suggest that social attraction, particularly audio, has potential for use in black-fronted tern conservation.