This kite is a widespread species throughout the temperate and tropical parts of Eurasia and parts of Australasia. Curiously, it is not found in the Indonesian archipelago between the South East Asian mainland and the Wallace Line. Vagrants, most likely of the Black-eared Kite, on occasion range far into the Pacific, out to the Hawaiian islands (AOU 2000).
European and central Asian birds (subspecies M. m. milvus and M. m. lineatus respectively) are migratory, moving to the tropics in winter, but races in warmer regions such as the Indian M. m. govinda (Pariah Kite) or the Australasian M. m. affinis (Fork-tailed Kite), are resident.
In the northern winter, it is therefore common to have a resident race and a distinguishable migrant form present together in these hotter areas.
In the United Kingdom, the Black Kite occurs only as a wanderer on migration. These birds are usually of the nominate race, but in November 2006 a juvenile of the eastern lineatus, not previously recorded in western Europe, was found in Lincolnshire.
Black Kites will take small live prey as well as fish, household refuse and carrion. They are attracted to fires and smoke where they seek escaping insect prey. They are well adapted to living in cities and are found even in densely populated areas. Large numbers may be seen soaring in thermals over cities. In some places they will readily swoop to take to food offered by humans, their habit of swooping to pick up dead rodents from roads often leads to them being hit by vehicles. They are also a major nuisance at some airports where they are considered important birdstrike hazards.
The Black Kite nests in forest trees, often close to other kites. In winter, many kites will roost together.
Recent DNA studies suggest that the yellow-billed, African races, parasitus and aegyptius, differ significantly from Black Kites in the Eurasian clade, and should be considered as a separate, allopatric species Yellow-billed Kite, M. aegyptius. They occur throughout Africa except for the Congo basin and the Sahara Desert.
On the other hand, the same study suggests that the Black-eared Kite (M. m. lineatus), sometimes separated as M. lineatus, is not sufficiently distinctive to justify specific status. As molecular information is much more reliable in this species than in the Red Kite, the Black-eared Kite should be regarded a distinct allopatric subspecies.