Taylor & Francis Group
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Wintering ecology and nomadic movement patterns of Short-eared Owls Asio flammeus on a subtropical island

posted on 2017-08-29, 14:16 authored by Wei Tseng, Wen-Loung Lin, Si-Min Lin

Capsule: Short-eared Owls Asio flammeus showed a female-biased sex ratio in their southernmost wintering grounds in Oriental Asia. This is the first description of a nomadic movement pattern in this area.

Aims: To investigate the sex ratio, movement patterns, home range size and habitat preference of non-breeding Short-eared Owls in subtropical Taiwan.

Methods: Eleven Short-eared Owls were radio tracked following trapping and transportation away from an airport as part of the management of bird-strike risk for aeroplanes.

Results: Our results indicated a female-skewed (75%) sex ratio for Short-eared Owls wintering in Taiwan. The owls demonstrated a nomadic behaviour by showing a repetitive pattern of high roosting site fidelity in the short term, followed by a long-distance movement to a different discrete area. Grasslands were commonly used as day-roosting sites but agricultural habitats were favoured at night.

Conclusion: Compared to on the breeding ground, the wintering owls exhibited a much larger home range size and exploit more dispersed patches of suitable habitats. These results revealed a notable conservation issue for the wintering owls, especially in the degraded and partially developed landscapes in subtropical countries.


This study was partially supported by grants from the Ministry of Science and Technology [MOST 105-2621-B-003-001-MY3 and MOST 105-2621-B-003-002-MY3].