The Black-shouldered Kite (Elanus axillaris) is a small raptor found in open habitat throughout Australia. Like all the elanid kites, it is a expert predator of rodents, its favorite prey.
The name “Black-shouldered Kite” was formerly used for a European and African species (Elanus caeruleus). The Australian bird (and also a North American species, the White-tailed Kite Elanus leucurus) were treated as subspecies of this. However the three species are now regarded as separate and the name Black-winged Kite is used for E. caeruleus. Modern references to the Black-shouldered Kite should therefore unmistakably mean the Australian species.
Black-Shouldered Kites are on average 35 to 38 cm in length and have a wingspan of between 80 and 95 cm. Adults are a very light grey with a white head and white underparts. The leading edge of the inner wing is black. When perched, this gives them their prominent black “shoulders”.
Although reported from almost all parts of Australia, they are most common in the relatively fertile south-east and south-west corners of the mainland, and in south-east Queensland. They are rare in the deep desert and appear to be only accidental visitors to northern Tasmania and the Torres Strait islands. Although sometimes found in forested areas, they are mainly birds of the grasslands. European occupation of Australia has, on the whole, benefited them by clearing vast expanses of forest for agriculture and providing suitable conditions for much larger numbers of mice.
Black-shouldered Kites live almost exclusively on mice. They take other suitably-sized creatures when available. These include grasshoppers, rats, small reptiles, birds, and even rabbits, however mice and other mouse-sized mammals account for over 90% of their diet. Their influence on mouse populations is significant: adults take two or three mice a day each if they can, and on one occasion a male was observed bringing no less than 14 mice to a nest of well-advanced fledglings within an hour.
Like other elanid kites, they hunt by quartering grasslands for small creatures. This can be from a perch (usually a dead tree), but more often by hovering in mid-air with great skill and little outward effort. Typically, a kite will hover 10 to 30 meters above a particular spot, peering down intently for only a few seconds and often for a minute or more, then glide swiftly to a new vantage point and hover again.
When prey is spotted, the kite drops silently onto it, feet-first with wings raised high; sometimes in one long drop to ground level, more often in two or more stages, with hovering pauses at intermediate heights. About two-thirds of attacks are successful. Prey can either be eaten in flight or carried back to a perch.