A Yellow-crowned Gonolek with entirely yellow underparts was discovered at Keur Gadj, Senegal, on 19 July 1989. It was paired with a normal individual and was regularly observed during the following seven years. Duetting appeared to be initiated by either bird. On 28 July 1990, the pair was accompanied by an apparently young bird, which also had yellow underparts. The aberrant adult remained in the area after the killing of its partner, in July 1993, and, while remaining unpaired, was regularly heard singing. It was last seen in September 1996.