I recently observed the courtship referred to earlier in this thread and took some pix to illustrate the behaviour. Mr Diderick would catch a caterpillar and offer it to the begging female while he proudly cocks his tail and hangs his wings in the universal male courting pose. This male hit upon a horde of caterpillars, sometimes arriving with another offering before the paramour had swallowed the previous present. Large view
Diderick cuckoos feed almost exclusively on caterpillars and termites. The pair thus forms a bond that extends to a play of distraction and deceit where the male cuckoo would have the potential host of his brood committed to chase him from their nesting site. While so occupied and their nest unattended, the female sneaks into the host’s nest and quickly deposits an egg. They mainly use bishops, weavers, sparrows and wagtails to play host to their chicks, actually removing any eggs present in the host's nest, sometimes even eating it some distance away. The female can lay up to 24 eggs during a breeding season, one egg per host's nest.
The cuckoos must be careful in their quest... if caught by the robust bishops and weavers, they risk serious injury. Having ringed numerous Cape, lesser masked and Southern masked weavers, I can attest to their ability to deliver a serious bite… certainly powerful enough to even kill a cuckoo. This misfortune befalling the Diderick has been witnessed previously.
The newly hatched Diderick cuckoo evicts any competition from the nest when it is 3 days old. It stays in the nest for about 19-22 days, and out of the nest, the chick remains with its adopted parents for about 21 more days. The juvenile Diederik looks much different from its parents, sporting a bright red beak and pale blue eyes, as shown in a portrait in an earlier post. With age the bill will turn black and the eyes red (if it is a male bird) or brown (if it is a female bird), so you cannot really confuse male, female and juvenile birds.
About half of the cuckoo chicks survive to nest-leaving age, making it a very successful bird!