Endogenous contributions to egg protein formation in lesser scaup Aythya affinis

Journal of Avian Biology
By: , and 

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Abstract

Lesser scaup Aythya affinis populations have declined throughout the North American continent for the last three decades. It has been hypothesized that the loss and degradation of staging habitats has resulted in reduced female body condition on the breeding grounds and a concomitant decline in productivity. We explored the importance of body (endogenous) reserves obtained prior to arrival on the breeding ground in egg protein formation in southwestern Montana during 2006–2008 using stable-carbon (δ13C) and nitrogen (δ15N) isotope analyses of scaup egg components, female tissue, and local prey items. From arrival on the breeding grounds through the egg-laying period, δ15N values of scaup red blood cells decreased while δ13C values became less variable; a pattern consistent with endogenous tissues equilibrating with local (freshwater) dietary sources. In 2006 and 2008, isotopic values for egg albumen and yolk protein indicated that most (>90%) protein used to produce these components was obtained on the breeding grounds. However, in 2007, a year with an exceptionally warm and dry spring, endogenous reserves contributed on average 41% of yolk and 29% of albumen. Results from this study suggest that female scaup can meet the protein needs of egg production largely from local dietary food sources. This highlights the importance of providing high-quality breeding habitats for scaup. Whether this pattern holds in areas with similar breeding season lengths but longer migration routes, such as those found in the western boreal forest, should be investigated.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Endogenous contributions to egg protein formation in lesser scaup Aythya affinis
Series title Journal of Avian Biology
DOI 10.1111/j.1600-048X.2011.05406.x
Volume 42
Issue 6
Year Published 2011
Language English
Publisher Wiley
Contributing office(s) Western Ecological Research Center
Description 9 p.
First page 505
Last page 513
Country United States
State Montana
Other Geospatial Red Rock Lakes National Wildlife Refuge