Great-tailed Grackle

Great-tailed Grackle

Art by Nancy McGowan

Quiscatus mexicanus

The Great-tailed Grackle has rapidly expanded its range in the United States in the 20th Century. The A.O.U. (1983) reported the breeding distribution as extending from the coasts of northwestern Venezuela, Colombia, Ecuador and northwestern Peru, north through both slopes of Middle America to southeastern and central California, southern Utah, northern New Mexico, southeastern Colorado, Kansas, southern Nebraska, southwestern Missouri, southwestern Arkansas, and southwestern Louisiana.

This species, once confined to the coastal plains in Texas, has steadily moved inland. Davis (1940) listed the bird as a ‘vagrant’ in Brazos county, but Petrides & Davis (1951) listed the Great-tail as a resident. By 1973, this grackle had become one of the most common residents in the county (Arnold 1973). Similarly, the bird ‘invaded’ the western parts of the state in the 1980s. In the northern part of the range, the Great-tail migrates south during the harsh months, but in the southern part it remains year-round. Even this status becomes complex by prevailing weather conditions: in central Texas, Great-tails remain throughout the year for the most part, but may move south onto the coastal plain during unusually harsh winters (Arnold & Folse 1977).

DISTRIBUTION: This grackle has a widespread distribution in Texas, with continuing expansion west and north. In the wooded portions of east Texas and in the western third of the state, the Great-tail is more-or-less restricted to human environs, especially towns and cities. Currently, the Great-tail has confirmed nestings in all vegetational regions of the state except for the Piney-woods.

SEASONAL OCCURRENCE: The Great-tail remains an abundant permanent resident in most of the southern half of Texas; in the northern portions, these grackles often migrate south when extreme winter conditions prevail. Typically, the males take up territories in late February or early March, and nest-building begins in mid- to late-March (Coon et al. 1971). With replacement clutches, nesting may continue into late July or early August (Arnold, unpubl. data). Coon et al. (1971) reported nesting attempts in mid-February.

Gotie (1972) reported onset of nest-building during the first week in April, but reported both interseasonal and between colony variation in initiation. He reported the peak of egg-laying in 1971 as the last week of April in all 3 colonies, while in 1972, two colonies had the peak in the second week of April, but the third colony had its peak in the first week of May.

The earliest date for nest with eggs among TBBAP data is 2 May (latilong 33097) and the latest date is 28 June 1987 (latilong 31102). However, the earliest date for nest with young among these data is 14 April 1990 (26098); thus, with a 13-l4 day incubation period, eggs were laid no later 31 March and likely several days earlier than that. The latest date for nest with young from the TBBAP data is 2 July (35101). Our studies on the Texas A&M University campus had early and late dates for nests with young as 2 May and 14 July. As banding of young normally takes place when young are 6-8 days of age, the last day in the nest for the 14 July date likely would extend to at least 20 July.

BREEDING HABITAT: Nearly 100 per cent of these grackles nest around human habitations. This may range from city parks and streets to farms. Great-tails avoid heavily wooded areas for nesting or foraging. They also avoid areas which are devoid of large trees. Grackle colonies almost always form in clumps of trees adjacent to or within one kilometer of pastures or lawns.

The large, bulky nest is placed in an upright crotch formed by limbs or, less likely, among several small branches at the end of a limb. On the Texas A&M campus, Great-tails mostly nest in live oaks (Quercus virginianus), but other large trees will suffice. The nest is constructed of grasses and small twigs, with a lining of fine grasses; however, the nest-builders often incorporate man-made materials such as toilet paper and plastic!

STATUS: All is well with the Great-tailed Grackle. Populations continue to grow and the species continues to expand its range. Indeed, this has become a pest species in many parts of Texas. A comparison with the map in Oberholser (1974) with the TBBAP map will quickly show how much expansion has taken place in the past twenty-two years.  Text by Keith A. Arnold (ca. 1993)

GTGLiterature cited
American Ornithologists’ Union. 1983. Checklist of North American birds, 6th ed. Am, Ornithol. Union, Washington, DC.

Arnold, K. A. 1973.  The birds of Brazos County: thirty years in  retrospect. Bull. Texas Ornithol. Soc. 6(1): 4-6.

Arnold, K. A. & L. J. Folse, Jr. 1977.  Movements of the Great-tailed Grackle in Texas.  Wilson Bull. 89(4): 602-608.

Coon, D. W., R. F. Gotie & K. A. Arnold. 1971.  Winter nesting attempts by Great-tailed Grackles.  Wilson Bull. 83(4): 440.

Davis, W. B.  1940. Birds of Brazos County, Texas. Condor 42: 81-85.

Gotie, R. F. 1972.  Nesting success of the Great-tailed Grackle (Cassidix mexicanus prosopidicola) in relation to certain density dependent and density independent factors.  M.S M.S.    Thesis, Texas A&M University, College Station.  87pp.

Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.

Petrides, G. A. and W. B. Davis 1951. Notes on the birds of Brazos County, Texas. Condor 53: 154-155.

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