Here in Aurora (IL), as winter's grip begins to loosen and the first hints of spring emerge, Carillon Stonegate Pond plays host to the return of the Common Grackle. These medium-sized blackbirds can be seen arriving in March, marking the beginning of their spring migration. These court jesters are a harbinger of the warmer months ahead, as they journey from their wintering grounds across the southern U.S. to take up residence in the diverse habitats of northern Illinois.
Identification: Common Grackles are medium-sized
blackbirds that appear entirely black from a distance. Adult males exhibit an
iridescent, glossy purplish-blue head and neck, coupled with a bronzy body
coloration. They possess long, black legs, a keel-shaped tail that accounts for
half their body length, sharp black bills, and yellow eyes. The average length
of a Common Grackle is just over 12 inches, including its long tail, with a
wingspan nearing 16 inches. Their weight averages around four ounces.
Habitat at Carillon Stonegate Pond: Common Grackles can be observed around
this area most of the year, from March through late fall. They are commonly
found on the ground beneath bird feeders and perched in trees.
Flight Patterns: During flight, Common Grackles travel
in a direct trajectory with relatively stiff wingbeats. In flight, their wings
seem short compared to their long tails, which fold down the middle into a
shallow V shape.
Behavior: Common Grackles are known for their
loud and boisterous behavior and typically travel in large groups, often
alongside other blackbirds such as Red-winged Blackbirds and Brown-headed
Cowbirds. They rest high up in trees and can be aggressive, sometimes driving
smaller birds away from feeders. A notable behavior is the “bill-tilt,” where
they tilt their heads upward with their bills pointed skyward to express
dominance.
Diet: Common Grackles are omnivorous, consuming a wide variety
of foods depending on the season. They predominantly eat seeds, including
sunflower seeds, acorns, tree seeds, and grains such as corn and rice. During
breeding season, their diet consists mainly of insects, along with crustaceans,
mollusks, fish, frogs, salamanders, and mice. In fall and winter, they revert
to eating seeds and grains. They primarily forage on the ground, moving aside
leaves to find food.
Residence: Common Grackles inhabit regions from
the Rocky Mountains eastward. In winter, their range is confined to the
Midwest, Southeast, and Central Atlantic states. In northern Illinois, they are
summer residents, while in southern Illinois, they are present year-round. They
prefer habitats with scattered trees for nesting and open ground for foraging,
such as open woodlands, forest edges, grasslands, meadows, swamps, marshes,
agricultural fields, suburbs, and urban parks.
Breeding and Nesting: Breeding occurs in spring, with nests
built among the dense branches of conifers or shrubs like cattails near
marshes. Up to five eggs may be laid, with the female incubating them for
approximately two weeks. Both parents feed the nestlings an insect-based diet
until they fledge after about three weeks.
Migration: In Kane County, Common Grackles
migrate, possibly over short distances. They arrive in March and remain through
spring and summer, typically migrating south by late October. In southern
portions of the Midwest, including southern Illinois, they are year-round
residents.
Conservation Status: Currently, there is low concern
regarding Common Grackles’ conservation status. Although populations have
declined by nearly 58% over the past five decades as per the North American
Breeding Bird Survey, they remain abundant and widespread. Partners in Flight
estimates the global breeding population at 61 million.
Vocalizations: Common Grackles are quite vocal, though
not very melodic. Their song is often likened to the sound of a squeaky, rusty
gate opening and closing. Link to the sounds of
the Common Grackle.
Interesting Facts:
- In winter, Common Grackles roost in large communal flocks with several different species of blackbird.
- The Common Grackle subspecies, found in New England and west to the Rocky Mountains, is known as the "Bronzed" Grackle because of its bronze body plumage.
- Common Grackles are one of the most significant agricultural pests, causing millions of dollars in damage to corn crops.
- The oldest recorded Common Grackle in North America was approximately 23 years old.
For more information on the Common Grackle and sources of information used in this blog (these are the sources that I am using to learn as I blog), please visit All About Birds, Audubon Society, Illinois Department of Natural Resources, University of Michigan’s Animal Diversity Web and American Bird Conservancy. And the Cornell Lab of Ornithology provides a wonderful source of information for anyone interested in learning more about birds.
We all benefit
from the variety of wetland, forest, and prairie environments that support
diverse wildlife, plants, and insects of Carillon Stonegate Pond.
Take
a hike and see what you can find – and identify!
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