The common crackle has a green/blue or purple iridescent tinted black plumage with a glossy purplish head, neck and breast with the female of the species, slightly smaller and duller colored. Boat-tailed and great-tailed grackles have very long “v” shaped tails which crease in flight, hence the name “boat-tailed”. They are similar in color to the common grackle but are larger birds (16 inches long versus 12” long). Female great-tails resemble the males while female boat tails are dark brown in color Great tails differ from boat tail grackles with their bright yellow eyes and more uniform color.
Damage Cycles
Grackles can cause several types of damage. As
they are scavenging birds, large numbers can be found at dumpsites, food
courts and other human areas where food is present. The resulting amount
of fecal matter creates unsanitary
conditions and can result in physical damage from the uric
acid. They are also an agricultural pest bird because they will eat small
seedlings and damage crops.
Control
There are numerous products and techniques available to combat nuisance
grackles. Like fellow members of the blackbird family, noisemaker units
such as the Bird-Gard,
Bird
Squawker and Bird
Wailer units projecting natural distress calls and frightening
sounds (selection of units depends on size of area to deter birds as well
as severity of problem) plus visual scare products like Scare
Eye Balloons, Octopus,
Flash
Tape and the Avikite
can be used to move them from a site. If they are too entrenched to be
scared away, exclusion using 1-1/8"
Stealth Net or Bird-Shock
electrical track on ledges will be necessary. Grackles are too nimble
for traditional mechanical ledge products. Fogging a roosting winter flock
with ReJeX-iT
irritant has also shown some success.
Nesting
Grackles build a bulky yet dense nest of twigs, grasses or weeds lined
with feathers, rags or dried grass. The nest may be held in place with
a foundation of mud or cow dung. Grackles will nest in a variety of places
from willow swamps, dense brush to tall trees with trees being the most
common. Boat tail grackle nests will seldom be seen more than twenty miles
from the coast.
Breeding
Grackles breed during the spring. They usually lay four to five eggs in
a single brood for the year. Common grackle eggs are a pale green to light
brown with purple and dark brown streaks and blotches. Boat tailed grackles
have lighter blue to grayish eggs with dark streaks and blotches. The
eggs take 14 days to incubate with the young being able to fly about three
weeks later.
Grackles have a definitive seasonal behavior. They nest and breed as one
pair or in small groups in the spring time. In the fall, the birds will
fall to form large colonies with the juveniles first forming the groups
and later joined by the adults. These large colonies can number in the
thousands. In colder, northern climates the flock will migrate south,
while southern birds will stay put or move into a more urban location.
These flocks will usually take over several trees or urban dwellings for
their evening roosting. In the winter, their feeding site may be quite
far from their roosting spot, making trapping or baiting difficult.
Grackle
Quick Facts Flight Speed Range Food Habitat Control
Height/Weight
12”/6oz common 16”/7oz boat-tailed Life span 8 to 12 years in the wild
20 to 35 mph
Common Grackle: Across U.S.,
east of Rockies
BoatTailed Grackle: Along Atlantic coast and gulf of Texas seaboard
Scavenger. Eats grains, seeds,
corn, insects,
food scraps, etc.
Prefer suburban areas with access
to open areas.
Roost in large trees during the winter.
1-1/8"
Stealth Net, Bird-Shock,
Audio/Visual
scare deterrents,
fogging with ReJeX-iT
