Field notes on the fan-tailed cuckoo

Abstract

In the field a distinction can usually be made between those Fan-tailed Cuckoos Cuculus pyrrhophanus that are darkly rufous below, perch prominently and call much and others that are paler below and unobtrusive and quiet. Five specimens of the first sort were all males and four of the second all females. Skins show that in general males are rather more dark rufous on the underparts than females. The trilling and whistling calls ofthe species seem to be given only by males. The females apparently produce only a 'chireee' call. These Cuckoos are often found in groups of three or more. While the males perch prominently and persistently trill and whistle, the females tend to skulk in thickets, giving the chireee call from time to time, often in response to the chireee of another bird. It is doubtful whether this is connected with territorial activity. Birds collected in 1977 were coming into breeding condition in late October and early November but in 1978 fresh eggs were found in the middle of October. In any case, the Cuckoos seem to come into breeding condition too late for the first broods of their chief biological hosts, Brown Thornbills Acanthiza pusilla and White-browed Scrubwrens Sericornis frontalis.