Tracking natal dispersal in a coastal population of a migratory songbird using feather stable isotope (δ2H, δ34S) tracers

PLoS One. 2014 Apr 16;9(4):e94437. doi: 10.1371/journal.pone.0094437. eCollection 2014.

Abstract

Adult birds tend to show high fidelity to their breeding territory or disperse over relatively short distances. Gene flow among avian populations is thus expected to occur primarily through natal dispersal. Although natal dispersal is a critical demographic process reflecting the area over which population dynamics take place, low recapture rates of birds breeding for the first time have limited our ability to reliably estimate dispersal rates and distances. Stable isotope approaches can elucidate origins of unmarked birds and so we generated year- and age-specific δ2H and δ34S feather isoscapes (ca. 180 000 km2) of coastal-breeding Ovenbirds (Seiurus aurocapilla) and used bivariate probability density functions to assign the likely natal areas of 35 males recruited as first-year breeders into a population located in northwestern New Brunswick, Canada. Most individuals (80-94% depending on the magnitude of an age correction factor used; i.e. 28-33 out of 35) were classified as residents (i.e. fledged within our study area) and estimated minimum dispersal distances of immigrants were between 40 and 240 km. Even when considering maximum dispersal distances, the likely origin of most first-year breeders was<200 km from our study area. Our method identified recruitment into our population from large geographic areas with relatively few samples whereas previous mark-recapture based methods have required orders of magnitude more individuals to describe dispersal at such geographic scales. Natal dispersal movements revealed here suggest the spatial scale over which many population processes are taking place and we suggest that conservation plans aiming to maintain populations of Ovenbirds and ecologically-similar species should consider management units within 100 or at most 200 km of target breeding populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Distribution*
  • Animal Migration
  • Animals
  • Canada
  • Conservation of Natural Resources
  • Feathers / chemistry
  • Female
  • Isotopes / analysis
  • Male
  • Songbirds / physiology*

Substances

  • Isotopes

Grants and funding

This study was supported by research grants from the Natural Sciences and Engineering Research Council of Canada (NSERC) to E.M.B., M.-A.V., and K.A.H., the New Brunswick Wildlife Trust Fund to M.-A.V., an operating grant from Environment Canada to K.A.H., and by a NSERC – J.D. Irving Ltd. Industrial Postgraduate Scholarship, NSERC Postgraduate Scholarship, Queen Elizabeth II Graduate Scholarship (University of Alberta), and a Dissertation Fellowship (University of Alberta) to S.H. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.