Female Corncrake (Crex crex) singing in the wild

Abstract

The male Corncrake (Crex crex) has a characteristic mating call. In aviary it has been shown that females can also produce a call similar to the male's typical 'crex crex'. I describe a strikingly different call produced by a female on Oland, southeast Sweden. The sex identification was based on the small size during close examination in the hand. The female call has a similar rhythm to the male call but lacks the rasping of the male and is almost a barking sound. The female was heard calling continuously at night throughout a three-week-period. Another bird producing the same call was heard about 100 m from the caught female suggesting two females in the same field. No male Corncrakes were heard in the field during the period when the female was calling. Possible explanations for this behaviour and the function of the call is discussed.