IS THIS PHILOPATRY OR DISPERSAL IN FEMALE BOREAL OWLS?

Abstract

Four cases of female Boreal Owls (Aegolius funereus) recaptured within varying distances of their natal or breeding sites are reported. We considered 3 recaptures within the natal or breeding neighborhood to be philopatry (site fidelity), and 1 case as dispersal. One banded female was recaptured as a 2y old, 3.4 km from her natal box. We considered this philopatry. She was later recaptured 15.8 km from her 2nd breeding site, and we considered this breeding dispersal. She lived at least 5 y, but we did not know her whereabouts in all years. A 2nd female banded as a nestling was recaptured 2.0 km from her natal box, breeding as a yearling (11 mo). We considered this natal philopatry. A 3rd female, previously banded as a breeding adult, was recaptured 2 y later breeding 2.5 km from her initial site of banding. We considered this philopatry. She was at least 4 y old. The 4th female was recaptured 3.6 km from her initial breeding box. We considered this philopatry. She was recaptured again the following year in the same nest box as her 2nd nest site. We considered the use of this same nest site philopatry. She was in her 5th calendar year. Our records are perhaps the 1st reports of natal philopatry and age of 1st breeding for female Boreal Owls in North America, and contribute additional records of female site fidelity and dispersal.