Juvenile survival in a neotropical migratory songbird is lower than expected

PLoS One. 2013;8(2):e56059. doi: 10.1371/journal.pone.0056059. Epub 2013 Feb 8.

Abstract

Attempts to estimate and identify factors influencing first-year survival in passerines, survival between fledging and the first reproductive attempt (i.e. juvenile survival), have largely been confounded by natal dispersal, particularly in long-distance migratory passerines. We studied Prothonotary Warblers (Protonotaria citrea) breeding in nest boxes to estimate first-year survival while accounting for biases related to dispersal that are common in mark-recapture studies. The natal dispersal distribution (median = 1420 m; n = 429) and a distance-dependent recruitment rate, which controls for effects of study site configuration, both indicated a pattern of short-distance natal dispersal. This pattern was consistent with results of a systematic survey for birds returning outside the nest box study sites (up to 30 km in all directions) within a majority (81%) of total available bottomland forest habitat, further suggesting that permanent emigration outside of the study system was rare. We used multistate mark-recapture modeling to estimate first-year survival and incorporated factors thought to influence survival while accounting for the potential confounding effects of dispersal on recapture probabilities for warblers that fledged during 2004-2009 (n = 6093). Overall, the average first-year survival for warblers reared without cowbird nestmates was 0.11 (95% CI = 0.09-0.13), decreased with fledging date (0.22 early to 0.03 late) and averaged 40% lower for warblers reared with a brood parasite nestmate. First-year survival was less than half of the rate thought to represent population replacement in migratory passerines (∼0.30). This very low rate suggests that surviving the first year of life for many Neotropical migratory species is even more difficult than previously thought, forcing us to rethink estimates used in population models.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Migration*
  • Animals
  • Ecosystem
  • Female
  • Illinois
  • Kentucky
  • Male
  • Reproduction
  • Songbirds*
  • Survival*

Grants and funding

Financial support was provided by the United States Fish and Wildlife Service (INT 1448-0003-95-1007), The Nature Conservancy, the Illinois Department of Natural Resources Wildlife Preservation Fund, the University of Illinois, the North American Bluebird Society, the Champaign County and Decatur Audubon Societies, and Sigma Xi. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.