The Great-tailed Grackle (Quiscalus mexicanus) is native to North and Central America. It primarily inhabits regions from the southern United States, including states like Texas, New Mexico, and Arizona, extending southwards through Mexico and into countries of Central America, such as Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica. The species has also expanded its range into regions like California and further north due to its adaptability.

Great-tailed Grackles are typically found in open and semi-open environments. They thrive in a variety of habitats, including urban and suburban areas, agricultural fields, wetlands, grasslands, and areas near water bodies such as lakes and rivers. The regions they inhabit generally have a warm climate with access to water and food resources.

In their native habitat, Great-tailed Grackles occupy the niche of an opportunistic forager. They have a varied diet that includes insects, small animals, grains, and human refuse, allowing them to adapt to both natural and urban environments. The species is known for its adaptability and ability to exploit new habitats, making them successful in expanding their range.