Translator Disclaimer
27 September 2019 Breeding origins and migratory connectivity at a northern roost of Vaux's Swift, a declining aerial insectivore
Author Affiliations +
Abstract

Populations of Vaux's Swift (Chaetura vauxi), like those of many aerial insectivores, are rapidly declining. Determining when and where populations are limited across the annual cycle is important for their conservation. Establishing the linkages between wintering and breeding sites and the strength of the connections between them is a necessary first step. In this study, we analyzed 3 stable isotopes (δ13C, δ15N, δ2H) from feathers collected during spring migration from Vaux's Swifts that perished during a stopover on Vancouver Island, British Columbia, Canada. We previously analyzed claw tissue (grown during winter) from the same individuals, revealing that the swifts likely wintered in 2 or 3 locations/habitats. Here, we used stable isotope analysis of flight feathers presumed to have been grown on, or near, the breeding grounds to determine the likely previous breeding locations and presumed destinations for the swifts. Stable isotope values (δ13C, δ15N, δ2H) showed no meaningful variation between age classes, sexes, or with body size. Surprisingly, ∼26% of the birds sampled had feather isotope values that were not consistent with growth on their breeding grounds. For the remaining birds, assigned breeding origins appeared most consistent with molt origins on Vancouver Island. Overall, migratory connectivity of this population was relatively weak (rM = 0.07). However, the degree of connectivity depended on how many winter clusters were analyzed; the 2-cluster solution suggested no significant connectivity, but the 3-cluster solution suggested weak connectivity. It is still unclear whether low migratory connectivity observed for Vaux's Swift and other aerial insectivores may make their populations more or less vulnerable to habitat loss; therefore, further efforts should be directed to assessing whether aerial insectivores may be habitat limited throughout the annual cycle.

Copyright © American Ornithological Society 2019. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
Ellis L. Smith, Matthew W. Reudink, Peter P. Marra, Ann E. McKellar, and Steven L. Van Wilgenburg "Breeding origins and migratory connectivity at a northern roost of Vaux's Swift, a declining aerial insectivore," The Condor 121(3), 1-12, (27 September 2019). https://doi.org/10.1093/condor/duz034
Received: 31 December 2018; Accepted: 16 May 2019; Published: 27 September 2019
JOURNAL ARTICLE
12 PAGES


SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top