Hawk owl irruptions: spatial and temporal variation in rodent abundance drive push and pull dynamics.

ABSTRACT: Bird irruptions are thought to be triggered by low food availability in breeding areas, thereby causing emigration (push factor). However, few studies have tested whether emigrating individuals are drawn towards areas of high food availability (pull factor). The Northern hawk owl (Surnia ulula), a rodent specialist, occurs irruptively to southern parts of Fennoscandia. We analysed whether irruption size during 1980-2020 in southeastern Norway was related to rodent abundance at four sites 450-990 km to the north-northeast (potential source areas) and at two sites in southeastern Norway to test push and pull dynamics of irruptions. Irruptions occurred when rodent abundance in potential source areas were low, supporting the push hypothesis. High rodent abundance in potential source areas 1-2 

SUBMITTER: Dale S 

PROVIDER: S-EPMC9813069 | biostudies-literature | 2023 Jan

REPOSITORIES: biostudies-literature