Common Grackle

About

The Common Grackle is a large, iridescent blackbird with a long tail and a stout bill. It is a highly adaptable species, often found in open woodlands, agricultural areas, and urban environments across much of North America. Known for its distinctive calls and social behavior, especially during migration and roosting.

Size & lifespan

Length

28-34 cm (11-13.4 in)

Wingspan

36-46 cm (14.2-18.1 in)

Weight

74-142 g (2.6-5.0 oz)

Lifespan

Average 4-7 years in the wild, up to 20 years recorded

Diet

Omnivore

Physical characteristics

Plumage

Adult males are entirely iridescent black, appearing purple, blue, green, or bronze depending on the light, particularly on the head and neck. The body is typically bronze-purple. Adult females are similar but often duller, with less intense iridescence and sometimes a slightly browner cast. Both sexes have a long, keel-shaped tail.

Beak shape

Stout, conical, and sharply pointed, black in color.

Eye color

Pale yellow, contrasting sharply with the dark plumage.

Leg color

Black

Distinguishing features

Large size, long keel-shaped tail (especially noticeable in flight), iridescent plumage, and bright yellow eyes.

Juvenile appearance

Juveniles are dull brown overall, lacking the iridescence of adults. Their eyes are dark brown, gradually changing to pale yellow over their first few months.

Seasonal changes

No significant seasonal plumage changes; iridescence may appear more vibrant in fresh plumage after molting.

Sexual dimorphism

Males are typically larger and have more pronounced iridescence than females. Females may appear duller and sometimes have a slightly shorter tail.

How to identify

1. 1

   Size and Shape

   Look for a relatively large, slender blackbird with a long, wedge-shaped body and a distinctive long, keel-shaped tail, especially prominent in flight.

2. 2

   Plumage Color and Iridescence

   Observe the overall glossy black plumage. In good light, look for iridescent sheens of purple, blue, green, or bronze, particularly on the head and neck. The body often has a bronze-purple hue.

3. 3

   Eye Color

   Note the striking pale yellow eyes, which contrast sharply with the dark head. This is a key field mark for adults.

4. 4

   Tail Shape

   Pay attention to the tail, which is long and often held in a V-shape or 'keel' during flight, especially when landing or taking off.

5. 5

   Vocalizations

   Listen for their characteristic harsh, squeaky, 'rusty gate' song and sharp 'check' calls.

6. 6

   Behavior

   Look for them foraging on the ground in open areas, often in flocks, or gathering in large communal roosts.

Habitat & range

Biomes

Forest edges, open woodlands, grasslands, agricultural fields, suburban parks, urban areas, marshes, and riparian zones.

Geographic range

Breeds across most of North America east of the Rocky Mountains, from central Canada south to the Gulf Coast of the United States. Winters primarily in the southern and eastern United States.

Elevation range

Typically found from sea level up to approximately 1,500 meters (5,000 feet).

Preferred environments

Highly adaptable, preferring open areas with scattered trees, often near water. Commonly found in human-modified landscapes such as parks, golf courses, and agricultural fields.

Behavior

Activity time

Diurnal

Feeding habits

Highly opportunistic omnivores. Diet includes a wide variety of insects (beetles, grasshoppers, caterpillars), spiders, earthworms, small fish, frogs, mice, eggs and nestlings of other birds, and carrion. They also consume significant amounts of seeds, grains (especially corn), berries, and fruits. They forage on the ground, in trees, and in shallow water. Known to 'dip' food in water before eating, a behavior called 'dunking'.

Social behavior

Highly social, especially outside the breeding season. They form large flocks, sometimes numbering in the thousands or even millions, often mixing with other blackbird species (Red-winged Blackbirds, European Starlings, Brown-headed Cowbirds) for foraging and roosting. During the breeding season, they are more territorial but may nest in loose colonies.

Flight pattern

Strong, direct, and somewhat undulating flight with steady wingbeats. The long, keel-shaped tail is often held in a V-shape during flight, especially when gliding or landing.

Migration pattern

Partial migrant. Northern populations are migratory, moving south for the winter. Southern populations are largely resident. Migratory movements occur in large flocks, often in late fall and early spring.

Territoriality

During the breeding season, males defend a small territory around the nest site. Outside of breeding, they are not territorial and gather in large communal roosts.

Breeding & reproduction

Breeding season

Typically April to July, with peak activity in May and June.

Nesting habits

Nests are usually built in dense trees or shrubs, often conifers, 3-10 meters (10-30 feet) above the ground. They may also nest in cavities, old buildings, or even on utility poles. Nests are bulky cups made of twigs, grasses, mud, and sometimes human debris, lined with finer materials.

Clutch size

3-7 eggs (average 4-5)

Egg description

3-7 eggs (typically 4-5), pale blue to greenish-blue, heavily marked with dark brown, purple, or black spots and blotches, especially at the larger end.

Incubation period

12-14 days

Fledging period

12-17 days after hatching

Parental care

Both parents participate in nest building, incubation (primarily female), and feeding of the young. Young are fed a diet rich in insects.

Where to find

Field tips

1. Look for Iridescence. The iridescent plumage is best seen in direct sunlight. Observe them from different angles to appreciate the shifting colors.
2. Listen for Calls. Their distinctive 'rusty gate' song and sharp 'check' calls are often heard before the bird is seen, especially in spring.
3. Observe Flocking Behavior. Outside of the breeding season, look for large, noisy flocks, often mixed with other blackbirds, foraging in fields or gathering at roosts.
4. Check for Yellow Eyes. The bright yellow eye is a crucial identification feature for adult Common Grackles, distinguishing them from some similar species.
5. Watch for 'Dunking' Behavior. If near water, you might observe them dipping food items into the water before consuming them.

Similar species

Quick facts

Distinctive Feature:

Bright yellow eyes and long, keel-shaped tail

Dietary Flexibility:

Highly opportunistic omnivore, adapting to available food sources

Social Behavior:

Forms massive flocks outside of breeding season

Vocalization:

Harsh, squeaky 'rusty gate' song

Habitat Adaptability:

Thrives in both natural and human-modified landscapes

Fun facts

• Common Grackles are known for their intelligence and problem-solving abilities, including using tools to access food.
• They engage in 'anting,' where they rub ants on their feathers, possibly to help remove parasites or to apply formic acid as a pesticide.
• Their long, keel-shaped tail acts like a rudder, helping them maneuver in flight, especially when landing.
• Common Grackles are one of the few bird species known to occasionally prey on other birds' eggs and nestlings.
• During migration and winter, their communal roosts can contain hundreds of thousands, or even millions, of individuals, creating spectacular aerial displays at dusk and dawn.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Passeriformes

Family

Icteridae

Genus

Quiscalus

Species

Quiscalus quiscula

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