Patterns of cowbird parasitism in the Southern Atlantic Coastal Plain and Piedmont.

Journal Article · Mon Sep 01 04:00:00 EDT 2003 · Wilson Bulletin

DOI:https://doi.org/10.1676/03-037· OSTI ID:835190

Kilgo, J C ^[1]; Moorman, C E

---

1. USDA Forest Service, Savannah River

Until recently, little information was available on patterns of brood parasitism by Brownheaded Cowbirds (Molothrus ater) in the southeastern United States, a region into which cowbirds expanded their range only during the last half of the Twentieth Century and where their abundance is relatively low. We compiled parasitism data from several published and unpublished studies conducted in Georgia and South Carolina from 1993-2000 to examine levels of brood parasitism and determine frequent host species. The combined dataset included 1,372 nests of 24 species reported in the literature to have been parasitized by cowbirds. The parasitism rate on all species combined was 8.2%. Considering only those species that served as hosts in these studies (n = I2), the parasitism rate was 9.3%. Seven species were parasitized at rates 2 10%. Based on the extent of parasitism (among studies and locations), their relative abundance, and the sample size of nests, Prairie Warblers (Dendroicta discolor), Hooded Warblers (Wilsonia citrina), Yellow-breasted Chats (Icteria virens), and Indigo Buntings (Passerina cyanea), all shrub nesters, appear to be the most important cowbird hosts in the region. Parasitism on some species reported as frequent hosts elsewhere was extremely low or not documented. We conclude that the impact of brood parasitism on the seasonal fecundity of hosts in the region probably is minimal, but additional work is warranted on species of concern, such as the Painted Bunting (Passerina ciris).

• Research Organization: USDA Forest Service, Savannah River, New Ellenton, SC
• Sponsoring Organization: USDOE Office of Environmental Management (EM)
• DOE Contract Number: AI09-00SR22188
• OSTI ID: 835190
• Report Number(s): na; 03-15-P
• Journal Information: Wilson Bulletin, Journal Name: Wilson Bulletin Journal Issue: 3 Vol. 115
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ABUNDANCE
Brood parasitism
GEORGIA
INDIGO
Molothrus ater
SHRUBS
SOUTH CAROLINA
brown headed cowbirds