The great-tailed grackle (Quiscalus mexicanus) is a large blackbird whose range presently includes the Western and Midwestern United States as well as Central America. This grackle is exhibiting a great increase in both range and population. In 1900 it had barely expanded into Southern Texas from Central America. According to one source the great-tailed grackle increased its territory 3.7% a year from 1966 to 1998.
About ten years ago Leonard saw a single great-tailed grackle, also commonly called a Mexican grackle, in Bieber CA (Lassen County). We never saw another grackle until about a week ago on the Tule River (Shasta County CA). These very loud, boisterous birds making constant, distinctive calls are difficult to ignore. On two occasions about four days apart we observed a small flock of great-tailed grackles. On our last trip to the area there were no grackles. Are those grackles moving into the area or were they passing through? The range maps for grackles show them nearby so great-tailed grackles may be further expanding into Northeastern California.
A social bird, the great-tailed grackle has a large, straight, thick black bill, long black legs and a yellow eye. The male is black with a violet-blue iridescence. A long (nearly as long as its body) deeply keeled tail makes this bird easy to pick out from the other blackbird species with which it often flocks. Female great-tailed grackles do not have a keeled tail. They are brown above and a paler brown on the belly and are slightly buffy on the head and throat.
Great-tailed grackles prefer open habitats with a nearby source of water although they can also be found in chaparral and second growth forests as long as there is water. Grackles will also venture into more urban areas. Although largely resident, grackles on the northern edge of their range will move southward following river valleys during the winter.
Great-tailed grackles eat plant material throughout the year. In the summer and fall grackles will also eat insects, snails, worms, slugs, tadpoles, frogs, bird eggs and nestlings, snakes and small mammals. Although they usually feed on the ground grackles will sometimes wade into shallow water for a fish or frog. Like gulls, grackles can be seen following tractors as they plow fields for the overturned insects, worms and other feed.