Sperm characteristics of male hybrid from a cross between male Black Grouse Tetrao tetrix and female Capercaillie T. urogallus

摘要

Crosses between Black Grouse Tetrao tetrix male and Capercaillie T. urogallus female are the most common grouse hybrids (Heglund and Porket 1989, McCarthy 2006). Such hybrids were recorded in Central Europe for the first time in 1744 (Johnsgard 1983) but likely must have been known earlier since ranges of these species overlap. Hybrids especially appear when a distortedsex ratio occurs in favor of Capercaillie hens. Porket (1990) indicated such a distortion in Central Europe did occur at the end of 19 h century and the beginning of 20 ' century when a large number of Capercaillie males were killed as a result of prestige-motivated spring hunting, and during the 1950s and 1960s. In the latter, anthropogenic factors are to blame for creating unfavorable environmental conditions for the survival of male Capercailliechicks.