Crows
General Crow Facts
Identification
The American crow is one of America’s best-known birds. Males and females are outwardly alike. Their large size (17 to 21 inches [43 to 53 cm] long), completely coal-black plumage, and familiar “caw caw” sound make them easy to identify.
They are fairly common in areas near people, and tales of their wit and intelligence have been noted in many stories.
Habitat
American crows do best in a mixture of open fields where food can be found and woodlots where there are trees for nesting and roosting.
They commonly use woodlots, wooded areas along streams and rivers, farmlands, orchards, parks, and suburban areas. Winter roosting concentrations of crows occur in areas that have favorable roost sites and abundant food.
Food Habits
Crows are omnivorous, eating almost anything, and they readily adapt food habits to changing seasons and available food supply. They belong to a select group of birds that appear equally adept at live hunting, pirating, and scavenging. Studies show that crows consume over 600 different food items. About one-third of the crow’s annual diet consists of animal matter, including grasshoppers, beetles, beetle larvae (white grubs, wireworms), caterpillars,
spiders, millipedes, dead fish, frogs,
salamanders, snakes, eggs and young
of birds, and carrion such as traffickilled
animals. The remainder of the
crow’s diet consists of vegetable or
plant matter. Corn is the principal food
item in this category, much of it
obtained from fields after harvest.
Crows also consume acorns, various
wild and cultivated fruits, watermelon,
wheat, sorghum, peanuts,
pecans, garbage, and miscellaneous
other items.
Damage and Damage
Identification
Complaints associated with crow
damage to agriculture were more common
in the 1940s than they are today.
Although surveys indicate that overall
crow numbers have not changed
appreciably, the populations appear to
be more scattered during much of the
year. This change has resulted apparently
from the crows’ response to
changing land-use patterns. Farming
has become more prevalent in some
areas, generally with larger fields.
Woodland areas are generally smaller,
and trees and other resources in urban
sites provide crow habitat. Overall, the
amount and degree of damage is
highly variable from place to place and
year to year.Several variables enter
into the complex picture of crow damage,
including season, local weather,
time of harvest, amount of crop production,
and availability and distribution
of wild mast, insects, and other
foods.
Visible crow damage inflicted on a pumpkin
Although crows cause a variety of
damage problems, many of these are
more commonly associated with other
animal species. Crows may damage
seedling corn plants by pulling the
sprouts and consuming the kernels.
Similar damage may also be caused by
other birds (pheasants, starlings, blackbirds)
and rodents (mice, ground
squirrels). Crows at times damage ripening
corn during the milk and dough
stages of development. Such damage,
however, is more commonly caused
by blackbirds; for further information,
see Blackbirds. Crows consume peanuts
when they are windrowed in
fields to dry, but other birds, especially
grackles, cause the greatest portion of
this damage.
Crows may also damage
other crops, including ripening grain
sorghum, commercial sunflowers, pecans, various fruits, and watermelons.
In rare situations, crows may
attack very young calves, pigs, goats,
and lambs, particularly during or
shortly after birth. This problem,
which is more often associated with
magpies or ravens, is most likely to
happen where livestock births occur in
unprotected open fields near large
concentrations of crows.
Another complaint about crows is that
they consume the eggs and sometimes
the young of waterfowl, pheasants,
and other birds during the nesting season.
Overall, such crow depredation
probably has little effect on the numbers
of these birds. However, it can be
a problem of concern locally, particularly
where breeding waterfowl are
concentrated and where there is too
little habitat cover to conceal nests. For
example, nests are more easily found
by crows, as well as by other predators,
when located in a narrow fence
row or at the edge of a prairie pothole
that has little surrounding cover.
Large fall and winter crow roosts
cause serious problems in some areas,
particularly when located in towns or
other sites near people. Such roosts are
objectionable because of the odor of
the bird droppings, health concerns,
noise, and damage to trees in the roost.
In addition, crows flying out from
roosts each day to feed may cause
agricultural or other damage problems. On the other hand, the diet of
crows may be beneficial to agriculture,
depending on the time of year and surrounding
land use (see sections on
crow food habits and economics).
Finally, in some situations, large crow
flocks may become a factor in spreading
disease. At times, they feed in and
around farm buildings, where they
have been implicated in the spread of
transmissible gastroenteritis (TGE)
among swine facilities. At other times,
large crow flocks near wetland areas
may increase the potential for spread
of waterfowl diseases such as avian
cholera. The scavenging habits of
crows and the apparent longer incubation
time of the disease in crows are
factors that increase the potential for
crows to spread this devastating disease.
Also, crow and other bird (blackbird,
starling) roosts that have been in
place for several years may harbor the
fungus (Histoplasma capsulatum) that
causes histoplasmosis, a disease that
can infect people who breathe in
spores when a roost is disturbed.
Legal Status
Crows are protected by the Migratory
Bird Treaty Act, a federal act resulting
from a formal treaty signed by the
United States, Canada, and Mexico.
However, under this act, crows may
be controlled without a federal permit
when found “committing or about to
commit depredations upon ornamental
or shade trees, agricultural crops,
livestock, or wildlife, or when concentrated
in such numbers and manner to
constitute a health hazard or other
nuisance.”
States may require permits to control
crows and may regulate the method of
take. Federal guidelines permit states
to establish hunting seasons for crows.
During these seasons, crows may be
hunted according to the regulations
established in each state. Regulations
or interpretation of depredation rules
may vary among states, and state or
local laws may prohibit certain control
techniques such as shooting or trapping.
Check with local wildlife officials
if there is any doubt regarding legality
of control methods.
Control
Crows may cause damage to agriculture, eggs, and even other animals. Let our Crow Control Professionals handle your crow problem. Call us now to find out how we can help!
*The above information was taken from a University of Nebraska Web site with
express permission of Stephen Vatassel, wildlife damage project coordinator.
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