The Eastern Kingbird ( Tyrannus tyrannus) is a familiar sight across much of North America, known for its bold behavior and distinctive black-and-white plumage. These birds are members of the tyrant flycatcher family, a group of New World species known for their insect-eating habits. While insects form the cornerstone of the Eastern Kingbird's diet during the breeding season, their dietary habits undergo a significant shift during migration and winter.
Identification and Behavior
"Bold" and "fearless" are words often used when birdwatchers describe the dashing Eastern Kingbird. The Eastern Kingbird is easily observed and identified in open habitats, with its black-and-white plumage and white-tipped black tail. Like other royalty, this "king" bird has a crown - a reddish-orange patch on top of its head that it flashes during defensive or mating displays. This patch, however, is rarely seen. Even in a group of birds known for their aggressive ways, the Eastern Kingbird stands out. The Eastern Kingbird truly deserves its Latin name of Tyrannus tyrannus. On its breeding grounds, it can often be seen attacking and chasing much larger birds, such as Red-tailed Hawks and Great Blue Herons, that make the mistake of flying through its territory. This pugnacious tyrant flycatcher has even been known to knock larger birds off their perches, including much heavier, nest-marauding Blue Jays.
Breeding and Nesting Habits
The male Eastern Kingbird woos his mate with elaborate flight displays and flashes of his bright crown patch. Pairs will often stay together successive years, even returning to the same territories. Although pairs are socially monogamous, extra-pair mating may occur, and chicks in one brood may have several different fathers. Eastern Kingbird populations tend to average more males than females, so a female kingbird often has more than one mate during her lifetime. The female typically builds her rather bulky, cup-shaped nest high in a tree, far out on a horizontal branch. This species occasionally nests in cavities and human-made structures as well. The female uses twigs, vegetation, and sometimes synthetic materials such as string or plastic to build her nest, finishing the interior with soft grasses and animal hair before laying a clutch of three to five eggs. She incubates her clutch for 16 to 18 days, her mate standing guard nearby to defend the nest and territory. If a nest is parasitized by a Brown-headed Cowbird, or, more rarely, another kingbird, the female recognizes and ejects the intruder's egg.
Summer Diet: An Insectivore's Delight
During the breeding season, the Eastern Kingbird is primarily an insectivore. Its diet consists mainly of large insects, including:
- Beetles
- Moths
- Wasps
- Bees
- Dragonflies
- Winged ants
- Grasshoppers
- Flies
- Leafhoppers
The Eastern Kingbird forages in typical flycatcher fashion, sitting quietly atop an exposed perch, then darting out to catch its prey on the wing. It sometimes hovers to glean insects from vegetation and even "kites" like an American Kestrel, facing into the wind on motionless wings while scanning the ground for prey. It may capture food in mid-air, or may hover while taking items (insects, berries) from foliage. In cold weather, when few insects are flying, may feed on ground.
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Eastern Kingbirds are particularly fond of open grassland or agricultural areas with scattered trees, plus woodlands, savannas, forest edges, and city parks, often near water. This preference for open habitats allows them to easily spot and pursue flying insects. The aggressive Eastern Kingbird is known for its habitat of chasing potential predators and brood parasites which it detects easily from its prominent perch. It also uses exposed perches to watch for flying insects which it sallies forth to snap up.
Attentive parents, Eastern Kingbirds provide their young with a steady supply of large insects, dead and with stingers removed if necessary. Both adults and nestlings regurgitate pellets of indigestible chitin, a fibrous substance in arthropod exoskeletons. The pair care for their young for three to five weeks after they leave the nest. As a result, they usually have enough time to raise only a single brood per season. However, Eastern Kingbird fledglings have a high survival rate, likely due to the extended period of parenting. Family units may remain together until fall migration begins.
Winter Diet: A Frugivore's Feast
During migration and on its wintering grounds, the Eastern Kingbird makes a dramatic dietary change, switching almost completely from an insectivore (insect-eater) to a frugivore (fruit-eater). Its northbound migration is well-timed to take advantage of peak fruiting season for Central American trees.
The Eastern Kingbird migrates to western South America and western Amazonia, where most individuals are intratropical migrants during the northern winter. While there, most individuals occupy two widely separated locations during the early and late nonbreeding period and maintain different social and feeding behaviors than during the breeding season. Most individuals travel in flocks and forage on fruit, returning to North America to begin laying eggs between late May and mid June.
The winter diet is not well known, but it is established that they feed heavily on berries in tropical forests. This dietary shift allows them to thrive in environments where insects are scarce during the colder months.
Read also: Red Bat Feeding Habits
Geographic Distribution and Habitat
Despite its name, the Eastern Kingbird breeds across much of the United States and Canada, with the exception of the arid Southwest, the West Coast, and the Arctic. In Texas Eastern Kingbirds prefer to breed at woodland edges, in pastures, orchards, trees on stream banks or in parks. The presence of water or moist habitats which probably increase the supply of its insect prey also seems important (Oberholser 1974).
Although fiercely territorial during its nesting season, the Eastern Kingbird becomes downright gregarious during migration and winter. It migrates during the day, often in flocks that increase to the thousands as the birds move south. On their wintering grounds in South America, Eastern Kingbirds remain in small feeding groups, sometimes with closely related Fork-tailed Flycatchers or Tropical Kingbirds, and gather in larger nighttime roosts.
Conservation Status and Threats
Although the Eastern Kingbird remains fairly common, Partners in Flight notes a downward trend in its numbers. One cause is habitat loss caused by human development, forest succession, and changing agricultural practices. Widespread pesticide use on breeding and wintering grounds, including the use of neonicotinoid insecticides, poses a major threat to aerial insectivores such as the Eastern Kingbird, Violet-green Swallow, and Common Nighthawk. Besides reducing insect-prey availability outright, these pesticides also accumulate in the birds' bodies and may lead to egg and nestling mortality. Eastern Kingbirds are frequently killed by collisions with cars since they tend to nest and forage in open spaces, many of which are bisected by roads.
Read also: Eating Habits: Eastern Coral Snake