Testing competing hypotheses for chronology and intensity of lesser scaup molt during winter and spring migration

The Condor
By: , and 

Links

Abstract

We examined chronology and intensity of molt and their relationships to nutrient reserves (lipid and protein) of Lesser Scaup (Aythya affinisK/i>) to test predictions of two competing hypotheses. The "staggered cost" hypothesis states that contour-feather molt is nutritionally costly and should not occur during nutritionally costly periods of the annual cycle unless adequate nutrients are available. The "breeding plumage" hypothesis states that prealternate molt must be complete prior to nesting, regardless of nutrient availability. Males and females were completing prebasic molt during winter (Louisiana) and had similar molt intensities. Females underwent prealternate molt during spring migration (Illinois and Minnesota) and prebreeding (Manitoba) periods; 53% and 93% of females were in moderate to heavy molt in Minnesota and Manitoba, respectively, despite experiencing other substantial nutritional costs. Intensity of prealternate molt was not correlated with lipid reserves even though females, on average, were nutritionally stressed. Molt intensity was not negatively correlated with protein reserves at any location. Chronology and intensity of prealternate molt varied little and were not temporally staggered from other nutritionally costly events. Prealternate molt did not influence nutrient reserves, and nutrient reserves likely were not the ultimate factor influencing chronology or intensity of prealternate molt of females. We surmise that nutrients required for prealternate molt come from exogenous sources and that the "staggered cost" hypothesis does not explain chronology of prealternate molt in female Lesser Scaup; rather, it appears that molt must be complete prior to nesting, consistent with the "breeding plumage" hypothesis.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Testing competing hypotheses for chronology and intensity of lesser scaup molt during winter and spring migration
Series title The Condor
DOI 10.1525/cond.2011.100055
Volume 113
Issue 2
Year Published 2011
Language English
Publisher Cooper Ornithological Society
Publisher location Waco, TX
Contributing office(s) Louisiana Cooperative Fish and Wildlife Research Unit, National Wetlands Research Center, Northern Prairie Wildlife Research Center
Description 8 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title The Condor
First page 298
Last page 305
Country United States;Canada
Google Analytic Metrics Metrics page
Additional metadata about this publication, not found in other parts of the page is in this table