Oecologia

, Volume 174, Issue 2, pp 595–608

Diffuse migratory connectivity in two species of shrubland birds: evidence from stable isotopes

  • Steven T. Knick
  • Matthias Leu
  • John T. Rotenberry
  • Steven E. Hanser
  • Kurt A. Fesenmyer
Conservation ecology - Original research

DOI: 10.1007/s00442-013-2791-8

Cite this article as:
Knick, S.T., Leu, M., Rotenberry, J.T. et al. Oecologia (2014) 174: 595. doi:10.1007/s00442-013-2791-8

Abstract

Connecting seasonal ranges of migratory birds is important for understanding the annual template of stressors that influence their populations. Brewer’s sparrows (Spizella breweri) and sagebrush sparrows (Artemisiospiza nevadensis) share similar sagebrush (Artemisia spp.) habitats for breeding but have different population trends that might be related to winter location. To link breeding and winter ranges, we created isoscapes of deuterium [stable isotope ratio (δ) of deuterium; δ2H] and nitrogen (δ15N) for each species modeled from isotope ratios measured in feathers of 264 Brewer’s and 82 sagebrush sparrows and environmental characteristics at capture locations across their breeding range. We then used feather \(\delta^{2} {\text{H}}_{\text{f}}\) and \(\delta^{15} {\text{N}}_{\text{f}}\) measured in 1,029 Brewer’s and 527 sagebrush sparrows captured on winter locations in southwestern United States to assign probable breeding ranges. Intraspecies population mixing from across the breeding range was strong for both Brewer’s and sagebrush sparrows on winter ranges. Brewer’s sparrows but not sagebrush sparrows were linked to more northerly breeding locations in the eastern part of their winter range. Winter location was not related to breeding population trends estimated from US Geological Survey Breeding Bird Survey routes for either Brewer’s or sagebrush sparrows. Primary drivers of population dynamics are likely independent for each species; Brewer’s and sagebrush sparrows captured at the same winter location did not share predicted breeding locations or population trends. The diffuse migratory connectivity displayed by Brewer’s and sagebrush sparrows measured at the coarse spatial resolution in our analysis also suggests that local environments rather than broad regional characteristics are primary drivers of annual population trends.

Keywords

Artemisiospiza nevadensis Migratory connectivity Sagebrush Spizella breweri Stable isotope 

Copyright information

© Springer-Verlag Berlin Heidelberg (outside the USA) 2013

Authors and Affiliations

  • Steven T. Knick
    • 1
  • Matthias Leu
    • 1
    • 3
  • John T. Rotenberry
    • 2
    • 4
  • Steven E. Hanser
    • 1
  • Kurt A. Fesenmyer
    • 1
    • 5
  1. 1.US Geological Survey, Forest and Rangeland Ecosystem Science Center, Snake River Field StationBoiseUSA
  2. 2.Center for Conservation Biology and Department of BiologyUniversity of CaliforniaRiversideUSA
  3. 3.Biology DepartmentCollege of William and MaryWilliamsburgUSA
  4. 4.College of Biological SciencesUniversity of MinnesotaSt. PaulUSA
  5. 5.Trout UnlimitedBoiseUSA