Post-Fledging Dispersal of Burrowing Owls in Southwestern Idaho: Characterization of Movements and Use of Satellite Burrows

摘要

Using radiotelemetry, we monitored dispersing juvenile Western Burrowing Owls (Athene cunicularia hypugaea) within a migratory population in southwestern Idaho during 1994 and 1995. Owls remained within natal areas for an average (± SE) of 58 ± 3.4 days post-hatching before moving permanently beyond 300 m, which was our operational cutoff for dispersal from the natal area. On average, owls dispersed on 27 July (range: 15 July to 22 August), which was approximately 4 weeks after fledging. After initiating dispersal, juveniles continued moving farther away from their natal burrows and, by 61-65 days post-hatching, they had moved 0.6 ± 0.2 km. Each juvenile used 5.1 ± 1.2 satellite burrows, and individual satellite burrows were used for up to 14 days. The average date on which we last sighted radio-tagged juveniles was 13 August, and all but one juvenile departed the study area by early September. Our study illustrates the importance of satellite burrows to dispersing Burrowing Owls.