Exploring Overlap of Feather Molting and Migration in Tundra Swans Using δ2H Analysis

Determining the processes that shape the relative timing of energetically-costly events in the annual cycle of migrating birds is important to our understanding of avian phenology and ecology. We paired satellite tracking and hydrogen stable isotope analysis (δ2H) to examine the relative timing of t...

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Bibliographic Details
Published in:Animal Migration
Main Authors: Wolf Nathan, Smeltz T. Scott, Welker Jeffrey M., Rogers Matthew C., Ely Craig
Format: Article in Journal/Newspaper
Language:English
Published: De Gruyter 2020
Subjects:
Online Access:https://doi.org/10.1515/ami-2020-0102
https://doaj.org/article/408f5c205a784d9a9fdb6412a3c00a7f
Description
Summary:Determining the processes that shape the relative timing of energetically-costly events in the annual cycle of migrating birds is important to our understanding of avian phenology and ecology. We paired satellite tracking and hydrogen stable isotope analysis (δ2H) to examine the relative timing of two such events – migration and feather molting – in tundra swans from four breeding areas in Alaska, USA. Our results show a trend of increasing intra-individual variability in breast feather δ2H values with increasing migration distance, suggesting the overlap of breast feather molting and migration. However, when individual samples were pooled by breeding area, the δ2H values of breast and head feathers showed no trend with migration distance, presumably resulting from high levels of inter-individual variability in δ2H values within each breeding area. We explore potential reasons for this variability, propose potential mechanisms influencing feather δ2H values of tundra swans, and recommend further research into methods for exploring the temporal configuration of events in the annual cycle of migrating birds.