Page 641 - Hand rearing birds second

642 Hand-Rearing Birds

These are social birds, often found in small to very large groups numbering thousands of birds.
Some species, including the American Crow and Florida Scrub Jay are cooperative breeders. The
birds as a group are omnivorous, with some species being heavily dependent on certain food items
including insects, nuts, cone seeds, and carrion. The focus of their diet fluctuates with the chang-
ing seasons and the natural foods available. Uneaten food is cached, a skill that should develop as
a juvenile matures.
The nest for this family is a bulky cup of sticks in a tree or other convenient tall structure. At
times some species will nest in a bush. Magpies add a roof when structurally possible and some
ravens nest on ledges and manmade structures.
Each species in the Corvidae family has specific behaviors relating to conspecifics and these behav-
iors may complicate release possibilities, especially if birds are not raised with siblings, similarly aged
juveniles, or adults of the same species. Adult ravens, for example, may be intolerant of older juve-
niles, forcing the juveniles to form a group to defend food finds from the resident adults. Raven nest-
lings vocalize loudly back and forth to one another after feeding, which is not typical of the other
species. Ravens have a different natural history compared to crows and the two species should not be
combined during the rehabilitation process. American Crows are cooperative breeders and may live
their entire lives within an extended family group. When unrelated crows need to be combined, there
will be a small amount of determination of the birds’ positions in the pecking order, but generally a
new addition will be accepted. Combining ravens requires care because older juveniles could prove
to be highly aggressive to a newcomer. Ravens move their young on within a few months after hatch-
ing and live their lives paired, as single birds foraging or roosting in groups of unmated individuals,
or in a group consisting of a mated pair plus a third bird. Once past the fledgling stage, ravens can be
aggressive to a new group member and there is a risk of injury to a newly introduced bird. The situa-
tion must be carefully monitored in a rehabilitation setting; but beware, these highly intelligent birds
may temper their aggressive behavior until they determine that you are not present. Magpies are also
extremely aggressive to an inferior or poorly socialized member of the species.
American Crows (Corvus brachyrhynchos) are common across most of America and can also be
found in Canada. Their diet is highly varied, including small animals, their young, and eggs;
insects; plant material such as seeds, grains, nuts, fruits, berries; plus carrion and garbage. The
Fish Crow (Corvus ossifragus) is found in flocks by marshes and lowland rivers of the eastern
United States, but in recent years has moved much farther inland following large river systems.
They feed primarily on animals, especially amphibians, crab, shrimp, small live fish, dead fish,
plus the eggs and chicks of other species in their habitat. They may flock with American Crows,
The Northwestern Crow (Corvus caurinus) is distinguished from other crow species by its limited
range in the coastal Pacific Northwest, intermixing with the American Crow in the most southern
parts of the range. This bird is omnivorous with a focus on marine environment items such as
crabs, shellfish, carrion, stranded fish, and the eggs of seabirds.
The Common Raven (Corvus corax), a species proven to be capable of stepwise thought, is an
omnivore with a focus on carrion. They will also prey on nestling birds, eggs, and vulnerable spe-
cies including mammals, amphibians, and reptiles. The Chihuahuan Raven (Corvus cryptoleucos)
is omnivorous with an emphasis on carrion.
The United States is home to two close-related species of magpie, the Black-billed Magpie (Pica
hudsonia) found in the northwestern part of North America and the Yellow-billed Magpie (Pica
nuttalli) found in central and southern California and nowhere else in the world. The Yellow-billed
Magpie favors more acorns in the diet than the Black-billed Magpie and tends to require the milder
climate found in sheltered valleys of California. They are highly social, so release of this species
requires definite knowledge of magpie appropriate territories.