Skip to main content
Article
Postfledging Survival of Grasshopper Sparrows in Grasslands Managed with Fire and Grazing
Condor
  • Torre James Hovick, Iowa State University
  • James R. Miller, University of Illinois at Urbana-Champaign
  • Rolf R. Koford, United States Geological Survey
  • David M. Engle, Oklahoma State University - Main Campus
  • Diane M. Debinski, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
1-1-2011
DOI
10.1525/cond.2011.100135
Abstract

More accurate estimates of survival after nestlings fledge are needed for population models to be parameterized and population dynamics to be understood during this vulnerable life stage. The period after fledging is the time when chicks learn to fly, forage, and hide from predators. We monitored postfledging survival, causespecific mortality, and movements of Grasshopper Sparrows (Ammodramus savannarum) in grassland managed with fire and grazing. In 2009, we attached radio transmitters to 50 nestlings from 50 different broods and modeled their survival in response to climatic, biological, and ecological variables. There was no effect of treatment on survival. The factor most influencing postfledging survival was age; no other variable was significant. The majority of chicks (74%) died within 3 days of radio-transmitter attachment. We attributed most mortality to mesopredators (48%) and exposure (28%). Fledglings’ movements increased rapidly for the first 4 days after they left the nest and were relatively stable for the remaining 10 days we tracked them. On average, fledglings took flight for the first time 4 days after fledging and flew 􀁱10 m 9 days after fledging. Our data show that the Grasshopper Sparrow’s survival rates may be less than most models relying on nest-success estimates predict, and we emphasize the importance of incorporating estimates of survival during the postfledging period in demographic models.

Comments

This article is from The Condor 113 (2011): 429, doi:10.1525/cond.2011.100135.

Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Language
en
File Format
application/pdf
Citation Information
Torre James Hovick, James R. Miller, Rolf R. Koford, David M. Engle, et al.. "Postfledging Survival of Grasshopper Sparrows in Grasslands Managed with Fire and Grazing" Condor Vol. 113 Iss. 2 (2011) p. 429 - 437
Available at: http://works.bepress.com/diane_debinski/21/