Formerly known as Derby Flycatcher, in honor of the Earl of Derby, or Kiskadee Flycatcher (based on its call), this large tyrannid flycatcher lives in river and lake margins, brushy savanna, scrub, and human-altered habitats throughout most of the New World tropics and subtropics. The Great Kiskadee's bright yellow underparts, black-and-white striped crown, and vocal habits reveal its membership in a large group of yellow-bellied flycatchers common in tropical lowlands of Central and South America. The black mask, so common in these and other open-country flycatchers, may help reduce the intense glare and aid in prey capture in their bright, tropical habitats ( Ficken and Wilmot 1968 , Ficken et al. 1971 ). Like all members of its family, the Great Kiskadee captures its share of flying insects on the wing, but its remarkable range of foraging behaviors and food items is broader than that of any other flycatcher in the New World. Kiskadee eat fish, tadpoles, a wide variety of fruits, and even visit backyard feeding stations to eat bananas, cooked rice, and dog food. Indeed, this tyrannid's generalized food habits, relatively large head and bill, and habit of capturing terrestrial and aquatic vertebrates make it more like a jay, shrike, or kingfisher than a typical flycatcher. Linnaeus ( Linnaeus 1766a ) recognized the Great Kiskadee's superficial similarity to shrikes by classifying it originally in the genus Lanius . Hudson ( Hudson 1920 ) remarked that it ". . . seems to have studied to advantage the various habits of the Kestrel, Flycatcher, Kingfisher, Vulture, and fruit-eating Thrush; and when its weapons prove weak it supplements them with its cunning."
A strikingly aggressive bird, Great Kiskadees will harass brown capuchin monkeys (Cebus apella), large raptors, toucans, or snakes that are attempting to rob their nests or those of nesting associates. They also defend their nests against brood-parasitic cowbirds, thereby greatly reducing the likelihood of raising young cowbirds. Great Kiskadees have been used in laboratory studies of the development of foraging and avoidance behaviors, including the innate avoidance of coral snake (Micrurus spp.) color-patterns ( Smith 1977e ).
Noisy and common in open tropical habitats, the Great Kiskadee is among the most familiar bird in plazas, parks, and rural countrysides of Central and South America. While among the most common native passerines in the largest cities (e.g., São Paulo, Brazil, and Mexico City, Mexico), it also is common along quiet jungle rivers and in desert scrub ( Fitzpatrick 1980a ). In unbroken tropical forest, the Great Kiskadee is limited to margins of rivers, oxbow lakes, and palm swamps, but local populations grow quickly around the clearings associated with humans. As a consequence, its range has expanded during the last century on both its northern (United States) and southern (Argentina) boundaries. Its ecological adaptability is demonstrated by its abundance today as an introduced species throughout the island of Bermuda.
The foraging behavior and diet of this widespread flycatcher have been reported for tropical and subtropical areas by Fitzpatrick ( Fitzpatrick 1980a ), Gorena ( Gorena 1995 , Gorena 1997 ), Cintra ( Cintra 1997 ), and Latino and Beltzer ( Latino and Beltzer 1999 ), among others. Gorena ( Gorena 1995 ) reported on its breeding biology near the northern edge of the range. Aggressive responses to predators were reported by Robinson ( Robinson 1997a ). Fitzpatrick studied foraging ecology, reproduction, and social behavior along a forested oxbow lake with marshy edges at Cocha Cashu Biological Station in the Manu National Park of southeastern Peru between May and December (dry season and early wet season) during portions of 1975, 1976, and 1977. Previously unpublished data from that study are included in this report, and so identified.