Translator Disclaimer
1 February 2001 EFFECTS OF BROWN-HEADED COWBIRDS ON THE NESTING SUCCESS OF CHIPPING SPARROWS IN SOUTHWEST COLORADO
Author Affiliations +
Abstract

We documented effects of Brown-headed Cowbird (Molothrus ater) parasitism on Chipping Sparrows (Spizella passerina) in southwest Colorado. Overall, 17 of 77 nests (22%) were parasitized. Abandonment was significantly higher among parasitized nests (29%) than unparasitized nests (5%). More Chipping Sparrows hatched and fledged per unparasitized nest than per parasitized nest. Reduction of host hatching and fledging rates in parasitized nests was attributable to smaller clutch size and higher abandonment. The major source of nest failure was predation, not parasitism; overall, 53% failed from predation, and only 6% failed from parasitism. There were no differences in weight, ulna length, tarsometatarsus length, or length of outermost primary between sparrow nestlings in parasitized and unparasitized nests. Only 18% of cowbird eggs laid resulted in a fledged cowbird. We observed no differences in nest placement or nest concealment between unparasitized and parasitized nests.

Catherine P. Ortega and Joseph C. Ortega "EFFECTS OF BROWN-HEADED COWBIRDS ON THE NESTING SUCCESS OF CHIPPING SPARROWS IN SOUTHWEST COLORADO," The Condor 103(1), 127-133, (1 February 2001). https://doi.org/10.1650/0010-5422(2001)103[0127:EOBHCO]2.0.CO;2
Received: 25 May 2000; Accepted: 1 October 2000; Published: 1 February 2001
JOURNAL ARTICLE
7 PAGES


SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top