Flightless and post-molt survival and movements of female mallards molting in Klamath Basin

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Flightless and post-molt survival and movements were studied during August-May, 2001-2002, 2002- 2003 and 2006-2007 for 181 adult female Mallards (Anas platyrhynchos). Birds were radiotagged just before or early in their flightless period on four wetlands that differed in size on Klamath Basin (KB) National Wildlife Refuge complex. Flightless survival varied among years but was higher on two larger than two smaller wetlands; 30-day survival ranged from 11% (SE = 6.5%) on a small wetland in 2006 to 93% (SE = 6.5%) on a large wetland in 2001, and averaged 76.8% (SE = 6.1%). Most flightless mortality was from avian botulism (64%) and predation (26%). Of the 81 radiotagged Mallards that did not die in KB, 80% moved to the Central Valley of California (CVCA) before 31 January, 16% wintered in unknown areas, and 4% remained in KB through 31 January. Mallards departed KB 21 August-13 January (average: 11 Nov 2001, 25 Oct 2002, 19 Nov 2006). Post-molt survival during August-March in KB (20.7%, SE = 6.3%) was lower than in CVCA during this (62.9%, SE = 10.1%) and an earlier study. Survival in KB was consistently high only for females that molted in large permanent marshes, and although the impact of poor survival of molting females on Mallard population dynamics is unknown, KB water management plans should be developed that maintain these habitats.

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Publication type Article
Publication Subtype Journal Article
Title Flightless and post-molt survival and movements of female mallards molting in Klamath Basin
Series title Waterbirds
DOI 10.1675/063.033.0209
Volume 33
Issue 2
Year Published 2010
Language English
Publisher The Waterbird Society
Publisher location Waco, TX
Contributing office(s) National Wildlife Health Center, Western Ecological Research Center
Description 13 p.
First page 208
Last page 220
Time Range Start 2001-08-01
Time Range End 2007-05-31
Country United States
State California, Oregon
Other Geospatial Klamath Basin (KB) National Wildlife Refuge complex
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
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