Owls
do exactly what children are warned against -- they swallow
their food whole, or nearly so. When they eat a small
vertebrate, they digest all but the bones and fur or
feathers. They regurgitate those remains in the form of a
hard, felted or feathered pellet -- one per victim. Where
owls feed on insects, each regurgitated pellet contains the
indigestible parts of the exoskeletons of numerous
individuals. Ejecting indigestible
portions of food in the form of pellets is also common in
raptors and gulls, and has been recorded in many other
groups of birds, including flycatchers, corvids, herons,
sandpipers, kingfishers, and even honeyeaters (primarily
Australian birds that supplement their nectar/fruit diets
with insects). Pellets, especially those of
birds that swallow their prey whole, provide ornithologists
with records of what the birds are eating at various times
and in various places. The hard pellets last a long time in
dry climates and can be collected in numbers near roosts. If
soaked in warm water, carefully dissected, and examined
under magnification, the identity of vertebrate prey often
can be determined from the bones. The pellets of raptors
such as eagles and hawks are less useful, since they tear
much of the flesh from their victims, and do not swallow the
bones. SEE: Diet
and Nutrition;
Determining
Diets. Copyright
® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl
Wheye.