Hawk-cuckoos closely resemble accipiters in terms of appearance, an elongated body with long wings and tail, greyish or brownish upperparts with paler barred upperparts, as well as their swift direct flight. Underpart barring, a form of
Batesian mimicry, tends to alarm small birds targeted by hawk-cuckoos for
brood parasitism beyond only shape and colour. The seemingly dangerous appearance of the cuckoo reduces host aggression or
mobbing, resulting in more opportunities for the cuckoo to parasitise the host. ==Species==