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Vibrant Blackbirds, Meet the Grackles

Updated on September 8, 2015
Sherry Thornburg profile image

Writer, photographer and birding enthusiast, Sherry Thornburg writes about birding and birding related topics.

Great-tail Grackle

Great-tail Grackle parking lot walking.  Taken along Brays Bayou in Houston Texas.
Great-tail Grackle parking lot walking. Taken along Brays Bayou in Houston Texas. | Source

Blackbirds aren’t always the ones we gravitate to when we get into birding. In time we do have to start paying attention, if for no other reason than their close proximity to urban and suburban areas and their sheer insistence on being noticed. Crows are noisy, Fish crows make contrasting company when seen with a flock of seabirds. Redwing blackbirds draw the eye to that bright red patch and little Brewer’s Blackbirds bathing in ponds demand attention in more subtle ways. But I find grackles to be the biggest showboats of the blackbird kind.

I started paying attention to grackles soon after moving back to Houston after being overseas for several years. I’m sure I had seen them before, but I didn’t remember how glossy they were or how their feathers turned purple, deep blue and other colors in the bright summer sun. It wasn’t until I started to study birds that I discovered there were three species.

Grackle Size Chart

Species
Length
Wingspan
Weight
Common Grackle
11 - 13 inches
14 - 18 inches
2.6 - 5 oz.
Boat-tail Grackle
11- 14.6 inches
15.4 - 10.7 inches
3.3 - 8.4 oz.
Great-tail Grackle
18.1 inches
22.8 inches
6.7 oz.
Grackle size ranges are a composite of data found at Cornell Labs, The Audubon Bird Guide and Sibley's Birds.

Telling Your Grackles Apart

In general, a grackle is a large blackbird, larger and heavier than most others except for Crows and Ravens. They have long thick bills and a long distinctive keel shaped tail. Females and juveniles are brown and can be rather drab looking, running smaller than the males.

The Common Grackle is the smallest and can easily be told from the others as the male has deep blue head feathers. Their bodies can shine bronze with a rainbow like iridescence. Their eyes are very pale in contrast. Females are similar to males but duller in color, not as iridescent. This is the most widely dispersed of the three species, ranging from middle Canada in the North down into Mexico and as far west as the Rockies. In Southern states, they tend to be year-round resident birds. Those living in Northern areas, however, migrate in huge flocks in spring and fall, usually combining with other blackbird species as they go. You can see how massive the flocks can get in the below video.

Mall Parking Lot Invasion

The Boat-tailed Grackles are mid-sized birds. They are more slender with a longer tail than the Common Grackle. Their iridescent coloring in the sun runs to blues and greens. This grackle is a coastal bird hugging east and southern regional salt marshes.

In Texas, this species has dark eyes, making them easier to tell apart from Great-tails. If I see brown-eyed grackle girls, I know I have Boat-tails. The females are usually the first ones I see in parking lots around my area.

The Great-tailed Grackle is the largest with the longest tail. The male’s tail is easily as long as the body. The Great-tail shines blue and purple on sunny days contrasting sharply with their pale cream eyes. The females tend to have a gray cast to their brown colors, making them a bit lighter than other female grackles.

This species used to be a stranger north of Mexico. They were once prized by Aztec Kings. Now they are found in the mid-west, southwestern states and California. They are expanding more westward each year and increasing in numbers. They share some territorial overlap with Common Grackles from the Mississippi River Delta to the eastern side of the Rockies.

Bird Study Suprise

For years, Great-tail and Boat-tail Grackles were considered the same species. It wasn’t until the 1970s that studies recognized that these birds cannot interbreed.

Grackles and Food

Boat-Tail Grackle fishing over reeds. Taken at Anahuac NWR.
Boat-Tail Grackle fishing over reeds. Taken at Anahuac NWR. | Source
Another Boat-Tail Grackle with a Crawfish. Taken at Anahuac NWR.
Another Boat-Tail Grackle with a Crawfish. Taken at Anahuac NWR. | Source
Great-Tail female and juveniles dinning at Fisherman's Warf in Galveston Texas.  Don't turn your back on these guys.
Great-Tail female and juveniles dinning at Fisherman's Warf in Galveston Texas. Don't turn your back on these guys. | Source

Grackle Appetites

Grackles, as a group, seem to eat about anything, arthropods, crustaceans, mollusks, frogs, fish, turtles, lizards, grains like corn and rice, seeds, and fruit. They will also eat small mammals like mice and shrews. They scavenge trash, scraps, steal from other birds, pet food bowls, and will even eat other birds and their eggs. Their territory seems to determine diet. If they come to your feeder it is likely you have grains in your feed such as cracked corn. Primarily ground feeders, they don’t bother backyard feeders much, but opportunity will bring them in.

As much as I love these birds, they aren’t the kind you want hanging in your yard. If they find your feeders you will likely get the whole flock. They will then chase off all the other birds in the area. I’m not a fan of chemical deterrents, and birds are smart enough to know a real owl or hawk from a plastic prop or recorded calls, so I can’t say how long such tactics would really work. Bringing in your feeders for a week or more might be the better option. If the birds are taking out your small garden or fruit trees, bird netting is considered the best way to keep them off.

There are feeders that work better than others to keep these large birds away. They might even keep squirrels out too. The feeders within cages are said to work well, such as the one below sold on amazon. For a full list of options see this page on bird control.

Farmers have the most trouble with these birds due to their love of corn, rice, sorghum and other crops. Grackles are known to chase tractors as they stir-up insects and flush out lizards, small rodents and other tasty prey. They also pull up corn shoots, which can poison them as many farmers use pesticide treated seeds. They are protected by the Migratory Bird Act, but sometimes they can be enough of a hazard that special permits are issued for their destruction.

In Houston, a shopping mall had been battling them for several years. Yes, we love our birds, but when they come in huge numbers, as you saw in the above video, the noise can be deafening at sunrise and dusk. Faced with their screeching whistling calls, they can become a major nuisance. After trying an air canon one year and scaring residents into calling in SWAT teams, the management switched to spraying area trees with Grape-seed extract. This wouldn’t hurt the birds, but they didn’t like the smell or getting it on their feet. The first year it was tried, in 2013, it seemed to work.

Grackles and Nesting

Great-Tail Grackle making display to mark and protect territory.
Great-Tail Grackle making display to mark and protect territory. | Source
Female Great-tail on nest built in tall grasses about  four to five feet from the water line. Taken at South Padre Island.
Female Great-tail on nest built in tall grasses about four to five feet from the water line. Taken at South Padre Island. | Source
Great-tail Grackles posturing before femaies in courting ritual. Taken near Roma Texas.
Great-tail Grackles posturing before femaies in courting ritual. Taken near Roma Texas. | Source

Grackle Family Life

Grackle breeding habits are different for all three species.

Common Grackles seem to choose single mates and nest in colonies protecting only their nest areas as territory. In spring, Cornell Labs accounts mention three kinds of playful chases: “first, a group of males will fly after a slow-flying female; second, a single male will chase a female at high speed; and third, a male and female will fly slowly and conspicuously alongside each other” announcing the pairing.

Boat-tails, on the other hands use “harem defense polygyny,” like deer herds. Females cluster their nests in a small area, and males compete to see which one gets to defend and mate with the entire colony. That is not to say the winner is the sole father of all chicks. The strongest male will mate with the larger portion of females, but others will also get a chance when the dominant male is away from the colony. DNA tests have shown that only about a quarter of chicks belong to the dominant male.

Great-tails are the ones seen performing a bird world’s version of a beauty pageant. The males will perch on some high object, car hoods in parking lots, fence rails and open tree branches, lifting their heads high, beak to the sky while their tails are fanned out. They do this singly and in groups. The groups will then sometimes devolve into tussling fights with males grappling feet and chasing each other. The pageant winners will then mate “with one or more “social mates” within their hard won territory and may try and mate with other females, while females have a single social mate, but may copulate with other males,” according to Cornell Lab’s Life History.

Females in all three grackle species brood and feed the chicks, while the male defends them from intruders. Part of protecting territories involves posturing as seen in the picture of the Great-tail at South Padre Island. This bird posed on high perches alternately fighting and chasing off other grackles. He also stood on the top of a bird viewing area I was using, which was close to a nest, scolding and making a major fuss until I left the area.

Chicks are born blind and mostly bare. In the juvenile stage, these birds are more dissimilar that they are as adults.

  • Common Grackles take 10 to 17 days or more to fledge. The juvenile tends to get their dark feathers early, starting with a dull dark brown with brown eyes. Their eyes will lighten as their feathers darken.
  • Boat-tails can take about 13 days to fledge. Boat-tail juveniles have pale buffy bodies and heads with darker wing feathers. As they mature, they develop a dark mask over their eyes.
  • Great-tails take 20 to 23 days to fledge. Great-tail young start out a more medium brown without the high contrasting pale face and dark mask Boat-tails have. They do have an eye stripe, but it is less noticeable.

Common Grackle during Molt

Taken in September at the beginning of Fall migration.
Taken in September at the beginning of Fall migration. | Source

Late Summer Molts

Unfortunately for our Grackle friends, molting season comes and causes their tail feathers to fall out. Kind of hard to strut your stuff when its gone. Flocks of tailless grackles can be a common sight in late summer and early fall. The tail grows back in a synchronized fashion with the longest feathers coming back last. Its an interesting molt pattern, and we suppose equally an affront to dignity to the molt patterns of Cardinals and Blue Jays, which loose their head feathers, going completely bald during molt.

Common Grackle Populations Declining

Common Grackle moving through the forest with its flock at Armand Nature Center, Texas.
Common Grackle moving through the forest with its flock at Armand Nature Center, Texas. | Source

Final Word

Final Word

Love them or hate them, Grackles are beautiful birds with lots of personality. They have learned to live with us. It seems now to be our turn to learn to live with them.

All three grackles are of least concern for conservation.

  • Even at least concern and being the most widely dispersed, Common Grackles are listed in the 2014 State of the Birds Report as a Common Bird in Steep Decline.
  • Boat-tails, restricting themselves to coastal waters are fewer in number and thus are watched for population declines carefully.
  • Great-tails are expanding westward and thriving in our urban and agricultural areas. Their populations are increasing at about three percent a year.

Happy Birding

© 2015 Sherry Thornburg

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    • m abdullah javed profile image

      muhammad abdullah javed 2 years ago

      Very interesting and informative sherry, in India we have a bird called crow, resembles with this beautiful bird. Since the bird can live amidst the human habitats, there is lot more for us to learn. Thanks for sharing.