Black-shouldered Kite - Elanus notatus
Common throughout much of mainland Australia, the Black-shouldered Kite is also occasionally recorded in northern Tasmania and on islands in Bass Strait. They usually inhabit grasslands and other open habitats, and with the expansion and establishment of agriculture in many regions, forested areas have been cleared, providing additional habitat, as well as extra food, in the form of House Mice, which forms a major part of the species’ diet. Occasionally large numbers of Black-shouldered Kites descend on a region, usually coinciding with plagues of mice or, occasionally, grasshoppers.
(Text Source: BirdLife Australia)