The Swallow-tailed Kite is the very epitome of graceful and sustained flight; the forked tail, often spread, but frequently opened and closed like a scissors, helps in manoeuvring. The size of this kite makes it more graceful in flight than smaller fork-tailed species like terns and swallows. It is usually seen on the wing, coursing over the country at various heights and often doing aerial gymnastics, especially during the breeding season. It is sometimes seen perched, especially during heavy grey weather. Although mostly a forest bird, it ranges over mixed country or even grasslands. It is a social species, especially on migration, when it is often in the company of the Plumbeous Kite. It tends to be a wanderer when not breeding. The Swallow-tailed Kite feeds on the wing. Insects are taken and eaten in flight. During the nesting season this kite searches for, and robs, the nests of small birds. Sometimes it carries away an entire nest, eating the fledglings as it flies along. It does not land, but may flutter for a few moments while taking a nest. It eats eggs as well as nestlings, and small lizards and arboreal snakes are also taken. It is social when feeding, as at other times. It drinks from the surface of a pond in the style of a swallow. This species is common in Suriname, it can be seen along the shores of Brokopondo lake and aside the long roads crossing the coastal plain.

Swallow-tailed kites occupy wooded swamps, open forests, lake shores, and freshwater marshes. They nest near sources of water in tall trees, anywhere from 18 to 40 meters above the ground.

Swallow-tailed kites are monogamous, although pair bonds are not necessarily maintained between breeding seasons. Females and males will approach each other on a horizontal tree limb. The female will quickly go under the limb or turn, bending forward with the wings extended. The male lands on her back and drapes his wings over the female, then mating occurs.
Swallow-tailed kites breed once per year, usually in April. They produce loud shrills, squealing calls, and whistles during the mating season. Females usually lay two eggs per clutch. The eggs are incubated for approximately 28 days, and the fledgling period lasts anywhere from 36 to 42 days. Fledglings can take an additional 2 weeks or more to become independent. Not much is known about the degree of parental investment in swallow-tailed kites. Both parents incubate the eggs. Young are altricial. Males bring back food while females watch the young and protect the nest. Towards the end of the nesting period both parents will hunt. After fledging the adults continue to provide food for their young.
As with some other kites there is a tendency towards social nesting: several pairs within a few hundred yards. Some nesting individuals, presumably hatched the preceding year, are not quite in fully adult feather.

Swallow-tailed kites are primarily insectivorous, snatching and feeding on flying insects in mid-air, but they are also known to capture other prey, such as snakes, frogs, and nestlings and fledglings. They do not hover and usually eat prey in mid-flight. They also drink in flight in a fashion similar to swallows, by skimming the water.

This species has a large range, with an estimated global Extent of Occurrence of 12,000,000 km². It has a large global population estimated to be 100,000-1,000,000 individuals (Ferguson-Lees et al. 2001). Global population trends have not been quantified, but there is evidence of a population increase (Ferguson-Lees et al. 2001), and so the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

Migratory in North and South of range. In late July, early August, large concentrations at communal night roosts (over 1300 birds leaving one morning) at Lake Okeechobee, Florida, apparently a staging post prior to southward migration. Departs from Peten by the end of August. Arrives in Costa Rica in January, all birds disappearing by July or early August. Arrives in Florida in March, in Peten in early February. Birds ringed in USA have been shot while wintering in South and South East Brazil. Over most of South American range, unclear where species is resident and where only migrant, as very few breeding records. Birds in breeding condition in South East Colombia (Vaupes), but otherwise most of Colombian birds may be migrants. In Amazonia, only one nest reported on upper Rio Negro, Brazil, although species doubtless breeds in the region. Nomadic at least in parts of South America over rain forest. Wanders to 2600 m in Andes of Colombia, and recorded at 5000 m near Lima, Peru. Accidental in Bahamas. Probably sedentary in Suriname, nests have been recorded.

article number 1 Title
SIBLICIDE IN SWALLOW-TAILED KITES
Author(s): RICHARD I? GERHARDT
Abstract: We studied the reproductive behavior of Swallow-tailed Kites (Elanoides forficatus) in northern Guatemala. Modal clutch size was two (range l-2), but no nests succeeded in fledging more than one young..[more]..
Source: Wilson Bull., 109(l), 1997, pp. 112-120
download full text (pdf)

article number 2 Title
PRE-NESTING BEHAVIOR OF THE SWALLOW-TAILED KITE (ELANOIDES FORFICATUS), INCLUDING INTERFERENCE BY AN UNMATED MALE WITH A BREEDING PAIR
Author(s): Lawrence Kilham
Abstract: Snyder( 1974) has described the breeding biology of the Swallow-tailed Kite (Elanoides forficatus). My observations of their pre-nesting behavior, made while staying at the Archbold Biological Station..[more]..
Source: Raptor Research 14(1):29-31
download full text (pdf)

article number 3 Title
FOOD DELIVERIES AT SWALLOW-TAILED KITE NESTS IN SOUTHERN FLORIDA
Author(s): KENNETH D. MEYER et al
Abstract: We studied the diets of nesting Swallowtailed Kites (Elanoides forficatus) at eight nests in 1988-1989 in southern Florida, where the species reaches its greatest abundance in the United States. Males..[more]..
Source: The Condor 106:171-176, 2004
download full text (pdf)

article number 4 Title
AGONISTIC BEHAVIOR IN THE SWALLOW-TAILED KITE
Author(s): W. BOYD BLIHOVDE
Abstract: The Swallow-tailed Kite ( Elanoides forficatus ) is an uncommon to fairly common visitor to wetland habitat of central Florida (Stevenson and Anderson 1994). This species is easily recognized by i..[more]..
Source: Florida Field Naturalist 30(2):41, 2002
download full text (pdf)