13C and15N enrichment in snipe (Coenocorypha spp.) from islands across the New Zealand biogeographic region

Abstract

The remaining five Coenocorypha snipes are restricted to remote islands in the New Zealand archipelago, so their ecology is difficult to study directly. To ascertain habitat types and ecological interactions across the different taxa and locations, we measured the δ13C and δ15N of feathers from known individual Auckland Island snipe C. aucklandica aucklandica (Adams I., n = 12; Enderby I., n = 4; Rose I., n = 8), Chatham Island snipe C. pusilla (Rangatira, n = 10), and Campbell Island snipe (Coenocorypha undescribed sp.; n = 1). Data for Snares snipe C. a. huegeli (North East I., n = 1) came from the literature. Developmental stage (nestling, juvenile, adult) and sex were statistically indistinguishable. Although significant differences in δ13C occurred between islands, the overall range was small (mean ± standard deviation, ‐22.7 ± 0.9%o). The restricted δ13C show that the snipe we sampled occupied a consistent habitat regardless of taxa, island size, and disturbance history. Conversely, the range in δ15N was large at c. 18.5%o and implied occupation of sites with a wide range of nutrient status. The δ15N from Adams I. (mean 5.9 ± 1.7%o) was much lower than the other islands (mean 19.2 ± 2.0%o) and could only be explained by including a15N‐depleted site not affected by seabirds or seals. Auckland Island snipe therefore integrate seabird breeding and non‐breeding areas as well as inhabiting locations with seals and high seabird densities. Consequently, Coenocorypha snipes provide connectances between marine animals on land and the wider terrestrial environment and so maybe considered for (re)‐introduction to predator‐proof mainland New Zealand restoration sites. © 2008 Taylor & Francis Group, Ltd.