Abstract
Many duetting species are monomorphic and the suggestion has recently been made that duets may be female-led more often than has been supposed in the past. Observations were carried out on several marked individuals of two monomorphic duetting species, the Moho, Hypergerus atriceps, and Yellow-crowned Gonolek, Laniarius barbarus, in The Gambia. DNA analysis from blood samples revealed that in each case the male was the pair member that normally led the duet. It is suggested that duets of this sort may arise where it benefits a male to attract more than one female, but it is to the female's disadvantage that he should do so.