Tyrannus tyrannus
eastern kingbird

Eastern kingbirds are the most widespread species in the genus Tyrranus. They breed throughout most of eastern North America, from the Gulf of Mexico north throughout much of southern and central Canada, as far east at the Atlantic seaboard to the Canadian maritime provinces, and as far west as central Texas, Colorado, northeastern Utah, eastern Oregon and Washington, and eastern British Columbia to the Yukon territories. They winter in South America, where their distribution is poorly understood but seems to be mainly in the western Amazon basin. (Murphy, 1996)

Eastern kingbirds are found in open, savanna-like habitats, often near water. They occur in fields and grasslands with scattered tall trees for nesting and perching. Suitable habitats include parks, riparian forests, large burned areas or blowouts in forests, golf courses, and suburban and urban areas. Little is know about their migratory habits, but they are found in a wide variety of habitats while migrating. In winter they are found in forest-edge, riparian forest, and near wetlands. (Murphy, 1996)

Eastern kingbirds are relatively small members of the genus Tyrannus, from 19.5 to 23 cm long. Males and females are similar, although males are slightly larger in all measurements. Males are distinguished from females by the notching of their 9th and 10th primaries, whereas only the 10th primary is notched in females. They are striking birds, with rich, black plumage dorsally and white plumage ventrally. They have an inconspicuous grey band across the chest. Kingbirds have an erectile crest of feathers on their head, although it isn't always observed. Males tend to erect their crown feathers more than females. Eastern kingbirds also have a small red or orange patch of feathers on the crown, which is rarely seen. They have a distinctive white trailing edge on the tail. The bill, claws, and legs are black. There are no recognized subspecies, but there is geographic variation in some measurements and in the width of the white tail tips. (Murphy, 1996)

Maximum lifespan is not reported for eastern kingbirds, but annual survival has been estimated at 54% for females and 69% for males. Most mortality in young is the result of predation. Causes of adult mortality are unclear, but may also be mainly predation. (Murphy, 1996)

Eastern kingbirds do not typically walk or hop, instead they fly from place to place. They are agile and fast flyers and perform several interesting aerial displays. They are active during the day and aggressively defend territories during the breeding season. They are very intolerant of the presence of other birds and have to overcome aggressive tendencies to form the pair bond at the beginning of the breeding season. They will not tolerate other eastern kingbirds nearby and will also harass other perching birds. During migration and winter, however, they are very social, forming large flocks of up to several thousand birds to migrate and staying in smaller foraging flocks of 10 to 20 in winter. (Murphy, 1996)

Eastern kingbirds migrate during the day in small flocks of 10 to 60, or sometimes up to thousands, of birds. They migrate overland mostly, but will form large flocks and cross water boundaries together. Northbound migrants begin to arrive in the United States in March, fall migration begins in late July and continues through September. Migrating flocks may stop over for several days in areas with abundant food. (Murphy, 1996)

Home Range

There is no information on home range sizes in eastern kingbirds. They aggressively defend territories during the breeding season, but nests may be as close as 30 m apart in areas with dense populations. (Murphy, 1996)

Eastern kingbirds use a variety of vocalizations to communicate, especially during the breeding season. In their winter range eastern kingbirds vocalize very little. Males sing a complex song in the pre-dawn hours, especially males in more dense populations. Calls are harsh and buzzing, often repeated "zeers." Males vocalize extensively when patrolling their nesting territory. Females vocalize as well, but males use vocalizations more frequently. Adults and juveniles will snap their bills at threats as well and they make whirring sounds with their wings occasionally. Courtship involves aerial displays between mates. (Murphy, 1996)

Eastern kingbirds eat insects during the breeding season and both insects and fruit outside of the breeding season. Insects make up 85% of the diet from May to September, including bees and wasps (Hymenoptera), beetles (Coleoptera), grasshoppers (Orthoptera), bugs (Hemiptera), and flies (Diptera). Insect prey is mainly taken by hawking from a perch. They dart out from perches to capture flying prey in their air. They will also take insects from the water or ground by hovering or gleaning. Small prey are eaten immediately, larger prey are taken back to the perch and smashed until they are subdued before being eaten. Larger prey are preferred. Fruit is taken in flight while hovering or gleaning as well. Eastern kingbirds do not seem to drink water. (Murphy, 1996)

Most predators target eggs and nestlings. Eastern kingbird adults are sometimes taken by aerial predators, such as American kestrels (Falco sparverius). Eastern kingbirds are aggressive and will energetically attack perceived threats, such as large hawks, crows, blue jays, squirrels, and snakes, whenever they are nearby. They will dive at a threat with their crest raised, exposing the red crown feathers, and with the mouth wide open, exposing their bright red gape. They will repeatedly attack the threat until they retreat. Eggs and nestlings are preyed on by crows (Corvus), blue jays (Cyanocitta cristata), squirrels (Sciurus and Tamiasciurus), and arboreal snakes. (Murphy, 1996)

Eastern kingbirds are important predators of insects during the breeding season. They eat fruits and may disperse seeds as well. They forage with other Tyrannus species in their winter range in South America, including tropical kingbirds (Tyrannus melancholicus) and fork-tailed flycatchers (Tyrannus savanna). They may nest near Swainson's or ferruginous hawks (Buteo swainsoni, Buteo regalis), both of which prey on common nest predators, such as crows and blue jays. Hatchlings are parasitized by mites, otherwise there is little known about parasites. Eastern kingbird nests are parasitized by brown-headed cowbirds (Molothrus ater) and other eastern kingbirds. (Murphy, 1996)

There are no adverse effects of eastern kingbirds on humans, although they may harass humans they perceive as threats near nests.

Eastern kingbird may help to control insect pest populations in some areas.

Eastern kingbirds are widespread and populations are large, they are considered "least concern" by the IUCN. They are protected by the U.S. Migratory Bird Act. (Murphy, 1996)