The common grackle (''Quiscalus quiscula'') is a species of large icterid bird found in large numbers through much of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. First described in 1758 by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

, the common grackle has three subspecies. Adult common grackles have a long and dark bill, pale yellow eyes, and a long tail. Adults often have an iridescent appearance on their head, especially males. Common grackles can be found widely across North America east of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

Taxonomy

The common grackle was first described in 1758 by

in the tenth edition of ''Systema Naturae'', as ''Gracula quiscula''. It was assigned to the genus ''

Quiscalus The avian genus ''Quiscalus'' contains seven of the 11 species of grackles, gregarious passerine birds in the icterid family. They are native to North and South America. The genus was named and described by French ornithologist Louis Jean Pierr ...

'' by French ornithologist

Louis Jean Pierre Vieillot Louis Pierre Vieillot (10 May 1748, Yvetot – 24 August 1830, Sotteville-lès-Rouen) was a French ornithologist. Vieillot is the author of the first scientific descriptions and Linnaean names of a number of birds, including species he collecte ...

in his 1816 ''Dictionnaire d'histoire naturelle''. Three subspecies are recognized: *the Florida grackle (''Q. q. quiscula'') (Linnaeus 1758), the

nominate subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

*the purple grackle (''Q. q. stonei'') (Chapman, 1935) *the bronzed grackle (''Q. q. versicolor'') (Vieillot, 1816)

Description

Adult common grackles measure from in length, span across the wings, and weigh . Common grackles are less sexually dimorphic than larger grackle species, but the differences between the sexes can still be noticeable. The male, which averages , is larger than the female, at an average of . Adults have a long, dark bill, pale yellowish eyes, and a long tail; their

feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...

s appear black with purple, green, or blue

iridescence Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...

on the head, and primarily bronze sheen in the body plumage. Adult females, beyond being smaller, are usually less iridescent; their tails in particular are shorter, and unlike the males, do not keel (display a longitudinal ridge) in flight and are brown with no purple or blue gloss. Juveniles are brown with dark brown eyes. When grackles are in a group, they are referred to as a "plague".

Distribution and habitat

The breeding habitat is open and semiopen areas across North America east of the

. The nest is a well-concealed cup in dense trees (particularly pine) or shrubs, usually near water; sometimes, the common grackle nests in cavities or in man-made structures. It often nests in colonies, some being quite large. Bird houses are also a suitable nesting site. Four to seven eggs are in a clutch. This bird is a permanent resident in much of its range. Northern birds migrate in flocks to the Southeastern United States. The distribution of the common grackle is largely explained by annual mean temperature, and the species has expanded its range by greater than three-fold since the last glacial maximum, approximately 22,000 years ago.

Ecology and behavior

Foraging and diet

The common grackle forages on the ground, in shallow water, or in shrubs; it may steal food from other birds. It is

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutri ...

, eating

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

minnow Minnow is the common name for a number of species of small freshwater fish, belonging to several genera of the families Cyprinidae and Leuciscidae. They are also known in Ireland as pinkeens. Smaller fish in the subfamily Leusciscidae are co ...

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

berries A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...

, and even small birds and mice. Grackles at outdoor eating areas often wait eagerly until someone drops some food. They rush forward and try to grab it, often snatching food out of the beak of another bird. Grackles prefer to eat from the ground at

bird feeder A birdfeeder, bird table, or tray feeder are devices placed outdoors to supply bird food to birds (bird feeding). The success of a bird feeder in attracting birds depends upon its placement and the kinds of foods offered, as different species h ...

s, making scattered seed an excellent choice of food for them. Grackles can be regularly seen foraging for insects, especially after a lawn trimming. Grackles have a unique adaptation in the keel within their bill which allows them to crack and cut hard nuts or kernels. The keel projects downward from the horny palate and is sharper and more abrupt anterior. It extends below the level of the tomium and is used in a sawing motion to score open acorns or dried kernels. Large adductor muscle within their jaw compared to other icterids also makes this adaptation even more useful for opening hard seeds and acorns. Along with some other species of grackles, the common grackle is known to practice "

anting Anting () is a town in Jiading District, Shanghai, bordering Kunshan, Jiangsu to the west. It has 96,000 inhabitants and, after the July 2009 merger of Huangdu (), an area of .

", rubbing insects on its feathers possibly to apply liquids such as

formic acid Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...

secreted by the insects.

Vocals

The grackle's song is particularly harsh, especially when these birds, in a flock, are calling. Songs vary from year-round ''chewink chewink'' to a more complex breeding season ''ooo whew, whew, whew, whew, whew'' call that gets faster and faster and ends with a loud ''crewhewwhew!'' It also occasionally sounds like a power line buzzing. The grackle can also mimic the sounds of other birds or even humans, though not as precisely as the

mockingbird Mockingbirds are a group of New World passerine birds from the family Mimidae. They are best known for the habit of some species mimicking the songs of other birds and the sounds of insects and amphibians, often loudly and in rapid succession. ...

, which is known to share its habitat in the Southeastern United States.

Breeding

In the breeding season, males tip their heads back and fluff up feathers to display and keep other males away. This same behavior is used as a defensive posture to attempt to intimidate predators. Male common grackles are less aggressive toward one another, and more cooperative and social, than the larger boat-tailed grackle species.

Relationship with humans

The range of this bird expanded west as forests were cleared. In some areas, it is now considered a pest by farmers because of its large numbers and fondness for grain. Despite a currently robust population, a recent study by the

National Audubon Society The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such organ ...

of data from the

Christmas Bird Count The Christmas Bird Count (CBC) is a census of birds in the Western Hemisphere, performed annually in the early Northern-hemisphere winter by volunteer birdwatchers and administered by the National Audubon Society. The purpose is to provide pop ...

indicated that populations had declined by 61% to a population of 73 million from historic highs of over 190 million birds. As a result, it is now classified by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

Near Threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

. Unlike many birds, the common grackle benefits from the expansion of human populations due to its resourceful and opportunistic nature. Common grackles are considered to be a serious threat to crops by some, and are notoriously difficult to control; this usually requires the use of hawks or similar large

birds of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predators ...

Proposed magnetoreceptivity

Though the exact mechanism is poorly understood, several studies have examined the ability of the common grackle to interpret the

Earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic f ...

—or in this case, the variability of it. The common grackle (like most of its ''

'' relatives) has been found to be attuned to a dynamic magnetic field to a scientifically significant degree.

Gallery

Image:Common Grackle - markings.jpg, Iridescent back and head Image:Common_Grackle - Iridescence.jpg, Iridescence in direct sunlight Image:Common_Grackle_Leucistic.jpg, Partially leucistic/

piebald A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots. The animal's skin under the white backgro ...

File:Baby grackle - Quiscalus quiscula.jpg, Chick File:An albino grackle photographed in Peterborough Ontario 2012.jpg, An albino grackle in

Peterborough, Ontario Peterborough ( ) is a city on the Otonabee River in Ontario, Canada, about 125 kilometres (78 miles) northeast of Toronto. According to the 2021 Census, the population of the City of Peterborough was 83,651. The population of the Peterborough ...

File:Grackle IMG 3972.jpg, Male feeding in grass File:Common_Grackle_(Quiscalus_quiscula).jpg, In Ontario, Canada

References

External links

*
Common grackle
- Cornell Lab of Ornithology
Audubon's Common Birds in Decline Report

Florida bird sounds including the common grackle
- Florida Museum of Natural History * {{Taxonbar, from=Q1424486

common grackle The common grackle (''Quiscalus quiscula'') is a species of large icterid bird found in large numbers through much of North America. First described in 1758 by Carl Linnaeus, the common grackle has three subspecies. Adult common grackles have a ...

Birds of North America Birds of Canada Birds of the United States

Articles containing video clips

Extant Pleistocene first appearances