The great-tailed grackle or Mexican grackle (Quiscalus mexicanus ) is a medium-sized, highly social passerine bird native to North and South America. A member of the family Icteridae, it is one of 10 extant species of grackle and is closely related to the boat-tailed grackle and the extinct slender-billed grackle. In the southern United States, it is sometimes simply referred to as "blackbird" or (erroneously) "crow" due to its glossy black plumage, and similarly it is often called cuervo ("raven") in some parts of Mexico, although it is not a member of the crow genus Corvus, nor even of the family Corvidae.
The Great-tailed grackle is a highly social bird from North and South America. Males are iridescent black with a purple-blue sheen on the feathers of the head and upper body, while females are brown with darker wings and tails. Adults of both sexes have bright yellow eyes, while juveniles of both sexes have brown eyes and brown plumage like females (except for streaks on the breast). Great-tailed grackles, particularly adult males, have a keel-shaped tail that they can fold vertically by aligning the two halves.
Great-tailed grackles occur from northwestern Venezuela and western Colombia and Ecuador in the south to Minnesota in the north, to Oregon, Idaho, and California in the west, to Florida in the east, with vagrants occurring as far north as southern Canada. They don’t migrate and are typically found in clear areas such as pastures, wetlands, mangroves, and chaparral. The grackles' range has also expanded with agricultural and urban settings.
Great-tailed grackles are active during the day and roost communally in trees or the reeds of wetlands at night. Their days are usually spent feeding in small groups in fields or urban parks. When Great-tailed grackles return to their roosting sites at dusk, they communicate with each other before taking preferred position. Great-tailed grackles have an unusually large repertoire of vocalizations that are used year-round. The sounds range from "sweet, tinkling notes" to a "rusty gate hinge". Males use a wider variety of vocalization types, while females use mostly in "chatter", however, it is suggested that they may perform the "territorial song".
Great-tailed grackles are omnivores and are noted for their diverse foraging habits. They extract larvae and insects from grassy areas and eat lizards, nestlings, and eggs. They also eat fruits (e.g., bananas, berries) and grains. They turn over objects to search for food underneath, including crustaceans, and worms, they hunt tadpoles and fish by wading into shallow water, catch fish by flying close to the water's surface, and are even reported to dive a few inches into the water to retrieve a fish. Great-tailed grackles also kill Barn swallows while flying.
Great-tailed grackles are polygynous; this means that males mate with more than females during the breeding season. These birds nest in territories using three different mating strategies: territorial males defend their territory on which many females place their nests and raise young; residential males live in the larger colony but do not defend a territory or have mates, and transient males stay for a few days before leaving the colony to likely move on to another colony. Territorial males are heavier and have longer tails than non-territorial males, and these characteristics are associated with having more offspring. Great-tailed grackles usually begin to breed in early or mid-April. The nest is typically built near the top of a large or medium-sized tree, using materials such as woven grass and twigs and some man-made materials. Females lay around 4 to 7 eggs and incubate them for around 13-14 days. The chicks typically leave the nest 12 to 17 days after hatching but parents continue to feed their young several weeks after they have left the nest until they reach maturity.
Because of their habit of eating young corn and sorghum sprouts, grapefruit, and other citrus groves, Great-tailed grackles are often seen as pests and persecuted by grain and citrus growers.
According to the All About Birds resource, the total breeding population size of the Great-tailed grackle is 30 million individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
