Description: Grackles, also known as the long-tailed
blackbird or the purple jackdaw, are native to the United States. There
are three distinct species of the grackle: great-tailed, boat-tailed, and
common, with the common divided into bronzed and purple races. Although
primarily seen in the southwestern and southeastern states, especially Kentucky
and Tennessee, grackles are expanding their territory. They are often
found in large, composite flocks of several species, such as red-winged
blackbirds. Grackles may be considered a pest species when they are
concentrated in such numbers that they constitute a nuisance or health hazard,
or are responsible for depredation to agricultural crops, livestock, wildlife
and ornamental or shade trees. Under these circumstances, a federal
wildlife permit generally is not needed to implement a bird management
program. However, state regulations vary.
Biology and Habits: Mature grackles may feed on
various types of grains, including corn, sunflowers, oats and rice. They
feed occasionally on small fish, field mice, and songbird nestlings and
eggs. The grackle prefers to roost in the upper branches of deciduous
trees.
Larger than a robin, this bird has a long wedge-shaped tail with a crease
down the middle, giving it a characteristic keel shape when the bird is in
flight. Other distinguishing characteristics include a long, sharp,
conical bill and yellow eyes. Although the feathers are predominantly dark
purple, they may also be iridescent, especially around the head, neck, and
shoulders.
Female grackles are smaller and less iridescent than males. A female
normally produces one clutch of 4 to 6 eggs in the spring. The eggs vary
in color, from blue to green to dirty brown, and are blotched or streaked with
black or brown. Both parents feed and care for the nestlings until they
leave the nest, usually within two weeks after egg hatch.
Control: Due to their large numbers in composite
flocks, grackles may pose health threats (mostly the spread of the fungus
Histoplasma spp.). In addition, grackles may damage agricultural
crops, deplete livestock feed in feedlots, and prey on songbirds or endangered
bird species.