The Effects of Management Practices on Grassland Birds—Rates of Brown-Headed Cowbird (Molothrus ater) Parasitism in Nests of North American Grassland Birds

Professional Paper 1842- PP
By: , and 

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Abstract

The Brown-headed Cowbird (Molothrus ater) is an obligate brood parasite that relies entirely on host species to incubate its eggs and rear its young. The Brown-headed Cowbird is a host generalist; eggs of the cowbird have been found in nests of more than 220 species of North American birds. Although cowbirds are not considered a serious threat to their primary avian hosts, cowbird brood parasitism has been recognized as a potential threat to the survival of threatened and endangered species and has been implicated in the declines of other bird species through reduced reproductive output. In this chapter, we summarized the rates of cowbird brood parasitism for 40 grassland bird species. The reported rates of brood parasitism by Brown-headed Cowbirds varied considerably among and within grassland host species, and the factors that influence parasitism rates were described. Defenses possessed by cowbird hosts in grasslands include aggressively defending their nests against female cowbirds, egg rejection, desertion of parasitized nests, and burying cowbird eggs in the nest lining.

Suggested Citation

Shaffer, J.A., Igl, L.D., and Johnson, D.H., 2019, The effects of management practices on grassland birds—Rates of Brown-headed Cowbird (Molothrus ater) parasitism in nests of North American grassland birds, chap. PP of Johnson, D.H., Igl, L.D., Shaffer, J.A., and DeLong, J.P., eds., The effects of management practices on grassland birds: U.S. Geological Survey Professional Paper 1842, 24 p., https://doi.org/10.3133/pp1842PP.

ISSN: 2330-7102 (online)

Table of Contents

  • Acknowledgments
  • General Overview
  • Rates of Cowbird Parasitism
  • Host Defenses against Parasitism
  • Summary
  • References

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title The effects of management practices on grassland birds—Rates of Brown-headed Cowbird (Molothrus ater) parasitism in nests of North American grassland birds
Series title Professional Paper
Series number 1842
Chapter PP
DOI 10.3133/pp1842PP
Year Published 2019
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Northern Prairie Wildlife Research Center
Description iv, 24 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title The effects of management practices on grassland birds
Online Only (Y/N) Y