The Great-tailed Grackle (Quiscalus mexicanus) is a large, conspicuous blackbird found in the southern United States, Mexico, Central America, and northern South America. Its scientific name comes from Latin: Quiscalus meaning “quiscal bird” and mexicanus meaning “Mexican”. This grackle gets its common name from its extremely long, keel-shaped tail. The Great-tailed Grackle is well-known for its adaptability and tendency to thrive around humans. But exactly where is the natural range and habitat of this opportunistic bird?
Natural Range
The Great-tailed Grackle naturally occurs across a wide swath of the Americas. Its breeding range extends from the west coast of California and Oregon in the United States south through western Mexico and Central America. On the east coast, it breeds along the Gulf of Mexico from Florida to Texas and south to Panama. The species has expanded its range dramatically in the last century, so its original native breeding areas are not fully clear. However, the core historic range likely centered around coastal and inland wetlands in western Mexico and Central America.
United States
Within the United States, Great-tailed Grackles nest primarily in areas near the coast or along major river valleys. They are found year-round along coastal southern California and in south Texas. Along the Gulf coast, their range stretches east to Florida. They also breed inland along major river systems like the Mississippi, extending north to Iowa and Minnesota. The species continues to expand northward and eastward across the continent.
Mexico and Central America
In Mexico, Great-tailed Grackles occur along both the Pacific and Gulf coasts. They are common residents through coastal areas from Sonora and Tamaulipas south to Chiapas. Inland, they occur widely but discontinuously in freshwater wetlands, lakes, and rivers. They are found south through Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, and Panama. Their breeding range likely historically centered in the coastal lowlands of western Mexico.
South America
The range extends south along the Pacific coast to northwestern Peru and along the Caribbean coast to northwestern Venezuela. Great-tailed Grackles occur marginally in suitable habitat in northern Colombia, otherwise being absent from most of South America. Their presence this far south may represent a relatively recent range expansion.
Habitat
Great-tailed Grackles use a variety of aquatic and semi-aquatic habitats across their broad geographic range. They are always associated with open water, riparian areas, and wetlands.
Coastal Habitats
Along the Pacific and Gulf coasts, Great-tailed Grackles frequent estuarine habitats, including mangroves,tidal marshes, lagoons, and mudflats. They also forage in sandy beaches, coastal strand, and salt marsh environments. Roosting and nesting occurs in stands of trees and shrubs within or bordering these coastal wetlands.
Inland Wetlands
Throughout their range, Great-tailed Grackles breed and forage in freshwater marshes, ponds, lakes, reservoirs, and slow flowing streams and rivers. Nesting occurs in stands of trees like willows along river courses. They are highly associated with emergent wetland vegetation across wetland types.
Human-Altered Areas
Great-tailed Grackles have adapted readily to human-created aquatic habitats. They occur year-round in parks, golf courses, cemeteries, athletic fields, drainage ditches, and retention ponds if open water and trees are present. Along with natural wetlands, man-made habitats likely helped spur their range expansions across North America.
Year-Round vs. Migratory Populations
Great-tailed Grackle populations can be resident year-round or migratory depending on location across their range:
Year-round
- Pacific Coast from Central California to Sinaloa, Mexico
- Gulf Coast from Florida to Veracruz, Mexico
- Much of western Mexico south to Costa Rica
In these regions, the species is present and breeds during the entire year. Harsh winters limit permanent residence farther north.
Migratory
- Interior U.S. from Central California and Texas east to the Mississippi River
- Along the Gulf Coast east of Veracruz, Mexico
- Interior plateaus of Mexico
In these areas, flocks migrate south for the winter and return in early spring to breed. Some inland Mexico populations may exhibit local movements between breeding and wintering areas.
Breeding Range Expansions
The Great-tailed Grackle has greatly expanded its breeding range over the past century:
- Radically expanded north in interior U.S. since 1900s
- Expanded along Gulf Coast and inland in southern U.S.
- Expanded north along Pacific Coast into Oregon
- Expanded inland in western Mexico
These expansions have tracked habitat changes and the availability of new food sources associated with human development. Their strong flight ability and adaptability to human areas have facilitated rapid dispersal and range expansion.
Causes
Several factors have enabled the species’ range expansions:
- Conversion of land to agriculture with irrigation canals and reservoirs
- Urbanization and creation of parks, golf courses, etc.
- Cattle feedlots and dairies providing grain food sources
- Increased food waste and landfills in human areas
- Milder winters enabling persistence farther north
Population and Conservation Status
Global Population
The global population of Great-tailed Grackles is estimated at 39 million individuals (Partners in Flight Landbird Conservation Plan). Global population trends are stable.
United States Population
In the U.S., Great-tailed Grackle populations have increased significantly in the past several decades:
- Estimated 1.1 million birds in 1966
- Estimated 18 million birds in 2012 (15x increase)
The U.S. populations are considered secure. They may compete with other blackbird species and considered a nuisance is some areas, but are not currently at conservation risk.
Conservation Status
The Great-tailed Grackle is considered a species of Least Concern globally and in the United States by the IUCN Red List due to its large and increasing population size and range. Partners in Flight estimates a U.S. population of 18 million birds and a global population of 39 million. The species is not in need of focused conservation efforts at this time.
Conclusion
In summary, the Great-tailed Grackle occupies a broad range across the southern United States, Mexico, Central America, and marginally into South America. Its core historic range centered along the Pacific and Gulf coasts of Mexico and Central America. Over the past century, it has expanded dramatically inland across much of North America due to ample food sources and habitat provided by human development. Though often considered a nuisance, Great-tailed Grackle populations remain secure across their range. Their adaptability looks likely to enable continued expansion and thriving among humans well into the future.