A McRae, of East Taieri, asks :-

Parental imprinting by infants, fixing upon the appearance, behaviour and calls of the adults, is so critical to the successful breeding of bird species that the cuckoo, brought up by other birds, must be singularly handicapped. How does a cuckoo, having never seen nor heard its parents during the crucial imprinting period, recognise the bird it must mate with to continue the cuckoo species?

Ian Jamieson, a zoologist at Otago University, responded.

Unlike most bird species, cuckoo offspring appear to block the normal imprinting process; this must have been a crucial step to the evolution of brood parasitism.

It had been thought that the offspring have an innate ability to recognise and mate with their own species without having seen them as offspring. However, it is now believed that adult male cuckoos remain in the vicinity of territories calling and that male and female cuckoo nestlings use this call that they hear as a template to develop their own calls (males) and for subsequent mate searching (females). So they do not imprint on the host species and do have an innate ability to recognise their species-specific calls, but develop individual characteristics/dialects from the male cuckoo they hear as a nestling.

A recent book by Nick Davies, "Cuckoo, Cowbirds and Other Cheats", (Poyser 2000) has recently been published to covers the behaviour of cuckoos in more detail.