Morphological and behavioral traits of a wild hybrid Eurasian Wigeon×Falcated Duck male found at Hyo-ko Waterfowl Park, Niigata, Japan

抄録

In the course of our fieldwork study at Hyo-ko Waterfowl Park, a local preserve in Niigata Prefecture, Japan, we found a male presumed wild hybrid between a Eurasian Wigeon Anas penelope and a Falcated Duck A. falcata in 2007; another or possibly the same individual was found again in 2009. The bird shared morphological traits with both species, although it was biased toward the Falcated Duck. Occasionally, the bird joined courting parties of Eurasian Wigeon, followed Wigeon females or competed with Wigeon males, and also showed courtship displays, e.g. Grunt-whistle, Head-up-tail-up, and Burping call, all of which were more like those of the Falcated Duck than those of the Eurasian Wigeon. Thus, the hybrid bird was sexually active to a considerable extent, but it remains unknown whether or not it actually formed a pair bond with a female of either parent species.