Program and Agenda

Abstract

COMBINING BREEDING BIRD SURVEY DATA WITH REMOTE SENSING TO ASSESS THE EFFECTS OF BREEDING AND WINTER CLIMATE ON THE RANGE-WIDE ABUNDANCE OF NEOTROPICAL MIGRANTS

Environmental factors affect migratory bird populations in every phase of their annual cycle and have significant impacts on breeding success and survival. The majority of studies have focused on environmental effects at small spatial scales, but range-wide analyses aid our understanding of how these effects influence population dynamics at the large scales over which conservation decisions are made. Recent advances in the analysis of the Breeding Bird Survey (BBS), remote sensing techniques and our knowledge of migratory connectivity allow us to examine how the range-wide abundance of a species is affected by environmental conditions at different stages of the annual cycle. Studies on two Neotropical migrants, the American redstart and Bullock’s oriole, used the Normalized Difference Vegetation Index (NDVI), a measure of vegetation greenness, as a productivity covariate in hierarchical models of BBS data. Abundance of American redstarts in eastern North America was positively influenced by winter productivity in the Caribbean where they over-winter but western breeding populations showed little response to productivity in their overwintering areas in Mexico. The abundance of Bullock’s orioles showed no response to environmental productivity during the non-breeding season (including moult and winter), but populations in the core area of the breeding range responded positively to conditions in the prior breeding season. The variable response to vegetation productivity across regions may be due to differing ecological mechanisms across a species’ range but also statistical limitations in our ability to link BBS abundance with environmental productivity. Improved knowledge on migratory connectivity and how ecological mechanisms affect individuals, especially during the non-breeding period, would improve our ability to assess how environmental conditions throughout the annual cycle affect species at large spatial scales.

Authors

Wilson, S., Environment Canada, Canada, scottd.wilson@ec.gc.ca

Pillar, A. G., Thompson Rivers University, Canada, andrew.pillar@gmail.com

Reudink, M. W., Thompson Rivers University, Canada, mreudink@tru.ca

Ladeau, S. L., Cary Institute of Ecosystem Studies, USA, ladeaus@caryinstitute.org

Tøttrup, A. P., University of Copenhagen, Denmark, aptottrup@snm.ku.dk

Marra, P. P., Smithsonian Migratory Bird Center, USA, marrap@si.edu

Details

Oral presentation

Session #:S13
Date: 9/26/2014
Time: 16:15
Location: Emerald Mountain - Bible Point

Presentation is given by student: No