Habitat
Subtropical and tropical dry forest and grassland, subtropical and tropical moist lowland forest, pemperate forest and grassland. From sea-level - 2,300 m.
Great-tailed Grackle (Quiscalus mexicanus) [XC488459]
by Guy Kirwan from Laguna Lake, San Luis Obispo County, California, Mexico (flight call)
Great-tailed Grackle (Quiscalus mexicanus) [XC731333]
by from Lajas Adentro, San Fel\u00edx, Provincia de Chiriqu\u00ed, Colombia (call)
Subspecies
Closely related to, and may form a superspecies with, Boat-tailed Grackle (Quiscalus major) and occasional hybrids between the two reported along coast of southern USA (in Texas and Louisiana). Related also to extinct Slender-billed Grackle (Quiscalus palustris) of central Mexican plateau. Recent study of mitochondrial DNA revealed two clades with deep sequence divergence (3·1%), one formed by western subspecies nelsoni and graysoni, the other including remaining subspecies. Despite DNA divergence, nelsoni hybridizes freely with monsoni in southern USA (California and Arizona) following range expansions in 20th century. In Mexico, nominate subspecies intergrades with obscurus in Guerrero (Balsas valley), with prosopidicola in southern Tamaulipas, and with loweryi in extreme western Campeche.
The following 8 subspecies are recognised:
nelsoni (Ridgway, 1901) - South-western USA (from central California, Nevada and south-western Arizona) south to north-western Mexico (northern Baja California and Sonora).
monsoni (Phillips, AR, 1950) - South-western USA (south-eastern California, central Arizona, Utah and Colorado south to New Mexico and western Texas) south to central Mexico (Zacatecas).
prosopidicola (Lowery, 1938) - Central and southern USA (from Nebraska south to central Texas and Louisiana) and north-eastern Mexico (Coahuila, Nuevo León and Tamaulipas).
graysoni Sclater, PL, 1884 - Coast of Sinaloa, in western Mexico.
obscurus Nelson, 1900 - Western coast of Mexico from Nayarit south to Guerrero.
mexicanus (Gmelin, 1788) - Central Mexico (from eastern Jalisco, San Luis Potosí and southern Tamaulipas) south to Nicaragua.
loweryi (Dickerman & Phillips, AR, 1966) - Yucatán Peninsula, including Cozumel I and other nearby islands, south to Belize.
peruvianus Swainson, 1838 - Costa Rica, Panama, and Colombia eastern on Caribbean coast to north-western Venezuela (Zulia) and southern along Pacific coast to western Ecuador and extreme north-western Peru (Tumbes).
BirdLife International Species Factsheet