The Pallid Cuckoo is a medium sized bird of similar size to a magpie perhaps. They can be particularly noisy when calling and one of their names ith the Brain Fever Bird because of its monotonous and repetitive call.
The pallid cuckoo (Cacomantis pallidus) is a species of cuckoo in the family Cuculidae. It is found in Australia, with some migration to the islands of Timor and Papua New Guinea. It is between 28 and 33 cm in size, with distinctive markings such as a dark bill, a dark eye with a gold eye-ring and olive grey feet which differentiate it from other cuckoos. The pallid cuckoo is similar in appearance to the oriental cuckoo (Cuculus optatus), with barred immature pallid cuckoos being often mistaken for oriental cuckoos.
“Pallid cuckoo” has been designated the official name by the International Ornithological Committee (IOC). Other common names include unadorned cuckoo, semitone-bird, scale-bird, and brain-fever bird—from its monotonous repetitive call.
Characteristics of the appearance of the pallid cuckoo include: a dark bill, a dark eye with a gold eye-ring, a shadowy dark mark from the eye down the neck, a white (or buff) mark on the nape, olive grey feet and prominent white (or buff) toothing along the tail. In flight, there are conspicuous white and dark bars across the long tail. Its silhouette resembles a falcon and often triggers alarm calls from passerines. The pallid cuckoo can have various morphs including light rufous morph or dark rufous morph.
In adult males the upperparts including head and neck are grey-brown and have large spots on wing-coverts. In adult females the light-rufous morph is similar to the adult male however with the dark rufous morph the hind neck patch extends onto mantle and it has barring on the chest.
A distinguishing feature of the family Cuculidae are the feet, which are zygodactyl, meaning that the two inner toes point forward and the two outer point backward.