The Swallow-tailed Kite (Elanoides forficatus) is a graceful and acrobatic raptor that breeds in the southeastern United States and spends its winters in South America. This medium-sized bird of prey is named for its deeply forked tail and swift, agile flight. Swallow-tailed Kites migrate thousands of miles each spring and fall between their breeding and wintering grounds. Understanding the migration path of the Swallow-tailed Kite provides insights into the biology and conservation of this fascinating species.
Breeding Range
The Swallow-tailed Kite breeds in the southeastern United States from eastern Texas and Oklahoma east to North and South Carolina and south to Florida. Its breeding range centers around the lower Mississippi River Valley and the coastal plains of the southeastern states. Swallow-tailed Kites nest in stands of tall trees near wetland areas such as swamps, marshes, and bottomland forests. They build shallow nests high in the tree canopy, often in dead snags. The nesting territory is aggressively defended by breeding pairs. Swallow-tailed Kites tend to nest in loose colonies, with nests located 30-460 feet apart.
Spring Migration
Swallow-tailed Kites spend the winter in South America, chiefly east of the Andes Mountains in areas such as the Pantanal wetlands and the Amazon River basin. As spring approaches, they begin a long migration north to their breeding grounds in the United States. The timing of spring migration varies with latitude; kites wintering at more southerly latitudes migrate earlier than those farther north. However, most Swallow-tailed Kites arrive at the northern Gulf Coast between late March and mid-April. This provides time to reach the breeding grounds, establish a territory, find a mate, and build a nest before the peak breeding period in May and June.
Spring migration takes place during the day with the aid of thermals and other updrafts that allow the birds to glide and soar with minimal wing flapping. Swallow-tailed Kites avoid making long water crossings during migration. Instead, they follow overland routes through Central America and Mexico into the United States. Banding data and sightings of tagged birds indicate two main spring migration corridors:
- Western route: From the Pantanal through Central America and Mexico into Texas and the Gulf Coast.
- Eastern route: From the Amazon Basin through eastern Brazil, eastern Mexico and the Yucatan Peninsula into the Gulf Coast states.
Breeding and Summer Range
Once Swallow-tailed Kites reach the breeding range, they disperse widely throughout areas of suitable habitat in the southeastern coastal plains and Mississippi River Valley. However, there are regional differences in summer abundance:
- Highest densities in Florida, Georgia, South Carolina, and eastern Texas.
- More scattered and localized farther west in Louisiana, Arkansas, Mississippi, and western Texas.
Swallow-tailed Kites occupy their breeding range from April through August. They nest in stands of tall trees near wetlands and forage widely over grasslands, marshes, lakes, and rivers. The diet is specialized, consisting mainly of large flying insects such as cicadas, grasshoppers, dragonflies, and crickets. Swallow-tailed Kites are aerial hunters and capture prey on the wing. They are also highly social, foraging, roosting, and nesting in groups. Nesting activity peaks in May and June, with one brood raised per season. The young fledge in 6-7 weeks and remain dependent on the parents for another month.
Fall Migration
In late summer and early fall, Swallow-tailed Kites gradually congregate into large pre-migratory roosts, sometimes numbering over 1,000 birds. These communal roosts are thought to be important for imparting migration routes and timing to younger birds. The timing of fall migration varies by latitude, beginning as early as July and August for kites summering farther north, and September to October for those farther south. Fall migration occurs over a broad front but follows similar overland corridors through Central America as in spring. However, the birds travel farther inland through Mexico in fall.
There are two main fall migration routes:
- Central corridor from Texas through Mexico into Central America.
- Western corridor through southwest Texas and Mexico into the Pantanal.
The pace of autumn migration is more relaxed than spring. Swallow-tailed Kites make frequent stopovers to feed and replenish energy before reaching the South American wintering grounds in late October and November.
Winter Range
The winter range of Swallow-tailed Kites spans much of South America east of the Andes Mountains. The core areas are the immense Pantanal wetlands at the Brazil-Bolivia border and the Amazon River basin. Other regions such as coastal Brazil, northeastern Argentina, Paraguay, and northeastern Peru are used to a lesser extent.
In the winter range, Swallow-tailed Kites occupy open and semi-open natural habitats near water, including tropical savannas, palm swamps, marshes, flooded forests and grasslands. Their winter diet shifts to include more bats, birds, reptiles, and insects. Swallow-tailed Kites remain in South America until the spring migration cycle begins again.
Threats to Migration
The long-distance migration of Swallow-tailed Kites makes them vulnerable to habitat loss and human impacts across their migratory flyways. Major threats include:
- Deforestation in Central and South America reducing habitat for feeding and roosting.
- Wetland drainage on the wintering grounds.
- Collision mortality from wind turbines and other structures.
- Illegal shooting and persecution.
- Climate change disrupting migration timing and food resources.
International cooperation is needed to monitor and conserve Swallow-tailed Kite populations throughout their migratory range. Protection of key stopover habitats and flyways in Central America is crucial.
Conclusion
The Swallow-tailed Kite undertakes an epic migration each year between its breeding range in the southeastern U.S. and wintering grounds in South America. By tracking banded birds and analyzing sightings data, ornithologists have pieced together the major migration corridors for this species. Swallow-tailed Kites migrate north over inland routes in spring, following corridors through Central America and Mexico into the Gulf Coast region. Fall migration occurs over a broader front through Mexico and Central America as the birds travel south. Although resilient and adaptable, Swallow-tailed Kites face increasing threats, especially the loss of wetland habitats critical for migration and wintering. Conservation of this aerial acrobat requires maintaining the chain of habitats along its migratory flyways across the Americas.