Geographic variation in dispersal of western burrowing owl (Athene cunicularia hypugaea ) populations across North America

Behavioral Ecology
By:  and 
Edited by: Macías-Duarte

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Abstract

Dispersal is one of the key elements of species’ metapopulation dynamics and, hence, influences global conservation status. Furthermore, determining the geographic variation in magnitude and direction of dispersal throughout a species’ distribution may expand our understanding of the causes of population declines in species of conservation concern. For instance, western burrowing owl (Athene cunicularia hypugaea) populations have declined at the northern and eastern edge of their breeding distribution during the 20th century. In the same period, large areas of thornscrub that did not support breeding owls were converted to irrigated agriculture in the southern edge of the subspecies’ breeding distribution in northwestern Mexico. These farmlands now support some of the highest breeding densities of owls. We tested the hypothesis that owls that colonized this recently created habitat originated from declining migratory populations from the northern portion of the subspecies’ range. We used stable isotopes 2H, 13C, and 15N in owl feathers to infer breeding dispersal patterns throughout the subspecies’ breeding range. Populations near the northern edge of the subspecies’ breeding range had immigrants that dispersed over larger distances than immigrants at low and mid latitude populations. However, agricultural populations in northwestern Mexico disrupted this latitudinal pattern, attracting owls from more distant locations. We also found immigrants originated from further distances in declining populations than increasing populations. Stable isotopes provided no evidence of contemporaneous breeding dispersal from Canadian populations to northwestern Mexico but suggest that agricultural areas in the southern edge of the subspecies’ distribution have altered the continental dispersal pattern.

Publication type Article
Publication Subtype Journal Article
Title Geographic variation in dispersal of western burrowing owl (Athene cunicularia hypugaea) populations across North America
Series title Behavioral Ecology
DOI 10.1093/beheco/arab100
Volume 32
Issue 6
Year Published 2021
Language English
Publisher Oxford Press
Contributing office(s) Coop Res Unit Seattle
Description 13 p.
First page 1339
Last page 1351
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