Common Grackle
Order: Passeriformes
Family: Emberizidae
Species: Quiscelus quiscula
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.
Before developing and implementing a bird management program, a qualified individual must thoroughly assess the public concerns and bird species involved with the projected program. The selection of available control agents must be evaluated for each given situation. The use of frightening devices may be effective in dispersing a flock from crops. Pyrotechnic devices, gas exploders, helium balloons with eyespots, reflecting tape, and recorded distress calls have been incorporated into management programs. Through repeated exposures, grackles, like other birds, may become habituated to the sounds emitted from devices and the images portrayed by visual displays. Therefore, programs must be periodically evaluated for their effectiveness.
Shooting
may enhance control results of a noise-related frightening program.
In addition, the chemical frightening agent and toxicant 4aminopyridine
(AvitrolŪ) is registered for both crop and non-crop use against these
pests.
Remember, check state and federal regulations governing bird control
and review specimen labels before implementing a bird management program.
(Courtesy of the National Pest Control Association.)