Pellet (ornithology)

The contents of a bird's pellet depend on its diet, but can include the exoskeletons of insects, indigestible plant matter, bones, fur, feathers, bills, claws, and teeth.

Many other species produce pellets, including grebes, herons, cormorants, gulls, terns, kingfishers, crows, jays, dippers, shrikes, swallows, and most shorebirds.

In the United States, screech owl pellets have contained bands from a tufted titmouse, black-capped chickadee, and American goldfinch.

In 1966, a golden eagle pellet in Oregon was found to contain a band placed on an American wigeon four months earlier, and 1,600 km (990 mi) away in southern California.

Hawks in the wild will produce castings of their own accord, in the form of small pellets of fur, feathers, and other indigestible material, regurgitated hours after it has eaten.

The yellow down feathers of day-old rooster chicks, which are a common diet among hawks in captivity, can be enough to induce casting.