THE ACQUISITION OF HOST-SPECIFIC FEATHER LICE BY COMMON CUCKOOS (CUCULUS-CANORUS)

This study addresses the question of how three species of flightless f eather lice (Phthiraptera) specific to a brood parasitic bird, the com mon cuckoo (Cuculus canorus), are transmitted from one cuckoo generati on to the next in the absence of any direct contact between parent and young. None of 21 cuckoo nestlings examined shortly before fledging c arried cuckoo lice; nor were any lice found in 19 nests in which cucko os had laid. Cuckoos returning to Japan for their first breeding seaso n were as likely to be lousy as, and carried similar louse loads to, o lder birds. These field observations are consistent with data arising from examination of museum skins from European breeding areas and from African wintering areas, and it is concluded that cuckoos acquire the ir lice between leaving the nest in summer and returning to the breedi ng grounds the following spring. This acquisition probably occurs via direct body-to-body contact between cuckoos, a supposition bolstered b y some observations.