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Relative value of managed wetlands and tidal marshlands for wintering northern pintails

Journal of Fish and Wildlife Management

By:
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DOI: 10.3996/102011-JFWM-062

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Abstract

Northern pintail Anas acuta (hereafter, pintail) populations have declined substantially throughout the western US since the 1970s, largely as a result of converting wetlands to cropland. Managed wetlands have been developed throughout the San Francisco Bay estuaries to provide wildlife habitat, particularly for waterfowl. Many of these areas were historically tidal baylands and plans are underway to remove dikes and restore tidal action. The relationship between tidal baylands and waterfowl populations is poorly understood. Our objective was to provide information on selection and avoidance of managed and tidal marshland by pintails. During 1991–1993 and 1998–2000, we radio-marked and relocated 330 female pintails (relocations, n =11,574) at Suisun Marsh, the largest brackish water estuary within San Francisco Bay, to estimate resource selection functions during the nonbreeding months (winter). Using a distance-based modeling approach, we calculated selection functions for different ecological communities (e.g., tidal baylands) and investigated variation explained by time of day (day or night hours) to account for differences in pintail behavior (i.e., foraging vs. roosting). We found strong evidence for selection of managed wetlands. Pintails also avoided tidal marshes and bays and channels. We did not detect differences in selection function between day and night hours for managed wetlands but the degree of avoidance of other habitats varied by time of day. We also found that areas subjected to tidal action did not influence the selection of immediately adjacent managed wetlands. If current management goals include providing habitat for wintering waterfowl populations, particularly pintail, then we recommend wildlife managers focus tidal restoration on areas that are not currently managed wetland and/or improve conditions in areas of managed wetlands to increase local carrying capacities

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Relative value of managed wetlands and tidal marshlands for wintering northern pintails
Series title:
Journal of Fish and Wildlife Management
DOI:
10.3996/102011-JFWM-062
Volume
3
Issue:
1
Year Published:
2012
Language:
English
Publisher:
U.S. Fish and Wildlife Service
Publisher location:
Arlington, VA
Contributing office(s):
Western Ecological Research Center
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Fish and Wildlife Management
First page:
98
Last page:
109
Country:
United States
State:
California
Other Geospatial:
San Francisco Bay