雄アカモズと雌チゴモズの種間つがいとその雑種

Abstract

On 21 July 2002 at Nobeyama Plateau in Nagano Prefecture, central Japan, we found an interspecific pair comprising a male Brown Shrike Lanius cristatus superciliosus and a female Thick-billed Shrike L. tigrinus, feeding their hybrid young aged about five days after fledging. The male and female parents and one hybrid young of about 28 days old were caught on 21 July, 22 July, and 31 July 2002, respectively. The parental plumage was typical for their respective species. The hybrid's plumage was entirely juvenile, with the remiges and rectrices growing. The juvenile plumage of the hybrid resembled that of Brown and Thick-billed Shrikes in some parts, but differed in many parts, notably in the colour and markings of the greater coverts and the face-mask. At the study area (ca. 15 km2) in 2002, only this interspecific pair and three pairs of Brown Shrikes were found breeding: no pairs of Thick-billed Shrikes bred. This is the first authentic case of hybridization of Brown and Thick-billed Shrikes in Japan.