Wing-spreading behavior as a possible threat display was observed in Japanese Paradise Flycatchers during the breeding season in northern Japan

Abstract

Wing-spreading behavior by Japanese Paradise Flycatcher Terpsiphone atrocaudata was observed 15 times among 12 breeding pairs in Iwate Prefecture northern Japan during 2013-2019. This behavioral display was observed from parent birds with fledglings nearby as the observer approached them during, before, and after the nestling fledged. It is possibly a threatening display against the intruder to protect the young.