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Impact of West Nile virus and other mortality factors on American white pelicans at breeding colonies in the northern plains of North America

Biological Conservation

By:
, , , , , , and
DOI: 10.1016/j.biocon.2008.01.019

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Abstract

American white pelicans (Pelecanus erythrorhynchos) are colonial-nesting birds and their breeding sites are concentrated in a few small areas, making this species especially vulnerable to factors that can influence productivity, such as disease, disturbance, predation, weather events and loss of nesting habitat. Nearly half of the American white pelican population breeds at four colonies in the northern plains: Chase Lake National Wildlife Refuge (NWR) in North Dakota, Bitter Lake (Waubay NWR) in South Dakota, Medicine Lake NWR in Montana, and Marsh Lake in Minnesota. Thus, sustained productivity at these colonies is crucial to the health of the entire species. During the latter half of the 2002 and 2003 breeding seasons, unusually high mortality of pelican chicks was observed at these colonies. West Nile virus (WNv) was identified as one source of these losses. In 2004-2007 we monitored three major colonies in the northern plains to assess mortality of chicks during the late breeding season. We documented severe weather events, disturbance, and WNv as factors contributing to chick mortality. Before WNv arrived in the region in 2002, chick mortality after mid-July was ???4%, and then jumped to as high as 44% in the years since WNv arrived. WNv kills older chicks that are no longer vulnerable to other common mortality factors (e.g., severe weather, gull predation) and typically would have survived to fledge; thus WNv appears to be an additive mortality factor. Persistence of lower productivity at American white pelican colonies in the northern plains might reduce the adult breeding population of this species in the region.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Impact of West Nile virus and other mortality factors on American white pelicans at breeding colonies in the northern plains of North America
Series title:
Biological Conservation
DOI:
10.1016/j.biocon.2008.01.019
Volume
141
Issue:
4
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Biological Conservation
First page:
1021
Last page:
1031
Country:
United States
State:
Montana, North Dakota, South Dakota
Online Only (Y/N):
N
Additional Online Files(Y/N):
N