Some like it odd: Long-term research reveals unusual behaviour in the flightless Kagu of New Caledonia

The observation of rare behaviours can provide unexpected insights into the biology of a species. Here, we report new observations of unusual or rare behaviours by the Kagu Rhynochetos jubatus of New Caledonia, a flightless bird already known for many curious traits. We observed the broken-wing display, adoption of a chick by a neighbouring family and flexibility in the selection of cooperative breeding partners in response to disruption in their social organisation. Although infrequent, these observations demonstrate the highly developed social flexibility that enables Kagu to counter heavy population losses caused by predation. We think that rare behaviours could often be overlooked in species because restricted research objectives might not allow their discovery.