Whistling kite

Description

The whistling kite ranges in size from 50–60 cm (20–24 in),with a wingspan between 123–146 cm (48–57 in).Weights range from 380–1,050 g (13–37 oz) an average of 600g-750g for males and 750g-1000g for females.As with most raptors,females are larger and heavier than males;though there is considerable overlap between the sexes,females can be up to 21% larger and 42% heavier.Southern birds are also larger than those found in the tropics.Male and female plumages are the same.Adult birds are a pale buff on the head,breast and tail,with browner wings and black flight feathers.Immature birds are a heavily streaked reddish-brown with prominent pale spots on the wings. Whistling kites soar on slightly bowed wings,with their long flight feathers often well-splayed.The striking pattern on their underwings is distinctive.This is a noisy species,calling regularly in flight and while perched—even while at the nest.Its most common call is a clear descending whistle,often followed (less often preceded) by a rapid series of rising notes.Intriguingly,field research carried out in Taunton Scientific National Park,Central Queensland by Fiona Randall from the University of Edinburgh,Scotland has shown that spotted bowerbirds (Chlamydera maculata) in that park regularly mimic the calls of whistling kites,with the frequency of mimicry increasing as the breeding season progresses.The function of this mimicry is unknown.