Eastern Kingbird

Tyrannus tyrannus



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Figure 4. Flocking during the nonbreeding season.

During the nonbreeding season, Eastern Kingbirds flock extensively both during migration and on the overwintering grounds (as shown here). In addition, they switch from a mainly insectivorous diet during the breeding season to one that includes mainly fruit. Drawing by J. Zickefoose.

Eastern Kingbird performing Wing-flutter Display.

Mates often greet one another using the Wing-flutter Display.

© Mark Berney, Florida, United States, 30 April 2017
Sunbathing Eastern Kingbird.

May sunbathe when perched at highly exposed sites.

© Keith Eric Costley, Maryland, United States, 19 August 2017
Eastern Kingbirds interacting.

Most kingbird communication relies heavily on both auditory and visual signals.

© Don Carbaugh, Maryland, United States, 25 June 2017
Eastern Kingbirds interacting.

Note exposed red crown patches.

© Nick Pulcinella, New Jersey, United States, 2 May 2016
Eastern Kingbird attacking Osprey.

This species will aggressively pursue raptors and large birds, especially during the nesting period.

© Tom Murray, Massachusetts, United States, 23 June 2017


Flight is virtually the only mode of locomotion; never walks when forced to go to ground (e.g., to obtain nest material or forage). Instead, short distances are covered by hops or more commonly by short flight. Appears to "walk" only when selecting a nest site. Female (and sometimes male) may move from one location in tree to another by short steps when inspecting possible nest sites. A strong flyer; can and will chase and drive swallows to the ground. Typically flaps wings continuously and rapidly, and flight is generally direct and fast, especially when hawking insects, chasing predators or conspecifics, or delivering food to young; rarely glides (but see below). Alternative foraging methods include hovering and "kiting" (see Diet and Foraging).

Several displays involve special flight maneuvers. Mates often greet one another using Wing-Flutter: individual beats wings very rapidly in shallow arcs and seems to "walk on air." Tumble-Flight Display (see Agonistic Behavior) incorporates Wing-Flutter, complicated series of twisting and flipping flights, and short gliding flights down to perch.


Preening, Head-Scratching, Stretching, Bathing, Anting, etc.

Preens frequently, females more than males (MTM, unpublished data). Females often run feathers through their bill and scratch themselves after episodes of nest-building, incubation, or brooding (MTM). Both sexes scratch their head with their feet while preening, and often end preening bout by stretching wings. Bathes by flying low over water and wetting breast and head. May repeat this behavior several times; followed by preening. Never observed to wallow-bathe at edge of water. Neither anting nor dust-bathing have been reported.

Sleeping, Roosting, Sunbathing

Females do not sleep on nest during egg-laying (140), but during incubation and probably first 7–10 d of nestling period, females remain on nest overnight. At other times pair roosts in trees near nest. A. Skutch (in 29) observed a large migratory flock in Central America that roosted nightly for nearly a month (early April–early May) on a tree-covered islet within the interior foliage of trees. During the nonbreeding season, large flocks of at least several thousand observed roosting in large trees in urban centers in Peru (R. B. Renfrew, personal communication). May sunbathe when perched at highly exposed sites.

Daily Time Budget

No specific information.

Agonistic Behavior

Physical Interactions

Territory establishment and pair formation entails considerable vocalizing, displaying, chasing, and occasional combat. Males are more active than females, but neighboring pairs may become involved in disputes in which individuals pair off and chase one another (MTM). It is not known whether same-sex individuals face off. Intrusions by single birds into an established territory may result in an aggressive chase by both resident male and female. Initially, male responds aggressively toward female and chases her at start of pair formation; gradually becomes accustomed to her presence. Mates continue to greet one another throughout breeding season with Wing-Flutter (see Locomotion) and chatter-zeer (see Sounds and Vocal Behavior: Vocalizations) (18).

Along a contested territory boundary, birds often face off with highly aggressive Crouch Display. One bird perches within about 1 m of another bird, holds body horizontally, points head at opponent (but with bill pointed downward), and spreads tail to display white terminal band. Flicks tail up and down frequently and ruffles feathers on head and dorsum. This display is generally given only in early breeding season during territory establishment. If a contestant does not retreat, an aerial fight often ensues. Fights involve locking of feet, pulling of feathers, and sometimes a fall to the ground.

Tumble-Flight Display is highly charged, dramatic display that functions as a ritualized form of aggression; male performs it by himself or simultaneously with neighbor. Occurs along territory boundaries, most often early or late in day, or after encounter with either conspecific or predator. Begins with upward flight on stiff, quivering wings (Wing-Flutter or hesitant flight) to height of 15–50 m above vegetation; after reaching full altitude, flight levels off, male flies slowly on quivering wings and then begins series of rapid twists in which the entire body is jerked several times 90° from horizontal plane; vocalizations are given frequently.

Communicative Interactions

Most Eastern Kingbird communication relies heavily on both auditory and visual signals (exception is dawn song [RRV]). Same vocalizations may have different meanings depending on visual information.



Territorial during breeding season, but boundaries often ill defined. Birds may feed off territory, especially during poor weather (low temperatures and/or rain). Early in breeding season and prior to egg-laying, territorial birds will disappear for periods of 1–2 d. Individuals carrying archival geolocators documented to relocate temporarily up to 250 km in response to severe weather (D. H. Kim, personal communication). Extent to which territory holder defends territory may depend on behavior of conspecific intruder, and male's aggressiveness toward other males may serve to ensure paternity or avoid territory takeovers. Experimentally removed males replaced (141), often within just hours (142). Likewise, removal of females results in rapid replacement, indicating that “floater” populations exist for both sexes (142) and that both sexes may have to defend against territory takeovers. One of 3 removed males (driven and released 150 km away) returned within 2 d to reclaim territory (142). Territoriality may also space nests to reduce impact of nest predators, but see 143 for Western and Cassin's (Tyrannus vociferans) kingbirds. In high-density populations, nests are occasionally placed only 30–40 m apart (MTM).

In Illinois, Graber and Graber (144) recorded the following densities (birds/40.5 ha): edge/shrubs, 33.5; shrub, 9.3; savannah, 7.2; fallow fields, 6.2; pasture, 5.7; red clover field, 1.8; mixed hay and mowed hayfields, 1.4; cornfields, 0.3. Excluding estimates for edge-shrub (unreasonably high) and cornfields (rarely nest near cornfields), density averages 5.3 birds/40.5 ha ± 3.10 SD (n = 6). Shugart and James (145) estimated that 6 territorial males occupied 40.5 ha in early successional habitats in Arkansas. Both density measurements yield estimated territory sizes that approximate average (8.4 ha) calculated from Odum and Kuenzler (146).

Anecdotal observations suggest no interspecific territoriality during breeding season. For example, a single small grove of trees in southern Kansas supported 3 pairs of Tyrannus, Eastern Kingbird, Western Kingbird, and Scissor-tailed Flycatcher (MTM), and in British Columbia, Eastern Kingbird and Western Kingbird nested within 90 m of one another (M. Funk, personal communication).

Individual Distance

Individuals very intolerant of conspecifics in early breeding season. Female overcomes male aggression to establish pair bond. Pairs generally remain intolerant of any species of bird near their nest (4, MTM). Female becomes aggressive toward male around hatching and sometimes keeps male away from nest for short period. Tolerance of other birds increases as season progresses, and occasionally a third adult Eastern Kingbird of either sex appears at nest (17, MTM). Family units remain isolated from one another, but sometimes coalesce as young become more independent (MTM). Flocks form gradually in late summer and continue through the overwintering period (73, 84, 120). See Distribution, Migration and Habitat: Migration.

Sexual Behavior

Mating System and Sex Ratio

The existence of a floater population of both sexes (142), equivalent median number of years lived by males and females (147), identical annual survival rates of the sexes (148), and equal survival rates of males and females raising typical brood sizes (13) are all consistent with an equal sex-ratio. Moreover, the sex ratio of young at fledging is 50:50 (149).

Socially monogamous mating system with widespread extra-pair paternity (1, 2). Occasional presence of third bird probably associated with failed reproduction and prospecting for future breeding site. McKitrick's (150) electrophoretic evidence suggesting that quasiparasitism (i.e., male with established pair bond mates with second female, and she lays in the male’s social partner’s nest) occurs has not been supported by results of studies using DNA fingerprinting (1) or microsatellite DNA (2). Although an egg rarely appears in a nest more than 2 d after the apparent end of egg-laying (MTM), DNA studies (n = 275 nests) have not revealed a single case of intraspecific brood parasitism.

One of the highest frequencies of extra-pair paternity known among passerine birds; 60% of nests typically contain extra-pair young and 50% of young sired by extra-pair males (1, 2; A. C. Dolan and MTM, unpublished data). Two extra-pair sires/brood not uncommon and it is normal for an equal proportion (ca. 35%) of males to either lose or secure all paternity in their nest (2; A. C. Dolan and MTM, unpublished data). Males that lose paternity slightly smaller (i.e., shorter tarsus) and weaker singer (later start time for Dawn Song and lower song rate) than the male who gained paternity at their expense (2). This system of ‘big winners’ and ‘big losers’ creates a significant opportunity for sexual selection (2) that presumably underlies the cryptic sexual size dimorphism of Eastern Kingbirds (31) and among female variation in brood sex-ratio. Although the sex ratio of fledged young is equal (50:50) when averaged over the season, females in good condition and/or breeding early in the year more likely to produce male young (149).

Pair Bond

Birds that have bred together previously pair quickly (151), but new pairs chase before pairing. Various observers (in 29) describe "courtship flight" in Eastern Kingbird as very rapid, zigzag flights accompanied by loud vocalizations, but Bent himself reported it as a series of short, quick dips, interspersed with level flight on quivering wings. Nothing is known about copulatory behavior because copulations have rarely been seen; by process of elimination, it is a virtual certainty that they occur early in morning during or just after the Dawn Song period.

Barring nest failure, most pairs remain together through the 3–5 wk period of post-fledging care (21), and possibly until migration. Males often follow mate closely during nest-building, possibly to guard against forced extra-pair copulations, or more likely, to guard against depredation. On basis of observations of banded birds, nearly all pairs remain together after nest failure if a replacement clutch is produced. Moreover, if both members of former pair return from South America to breed again, they usually reform pair bonds (85% of 32 pairs) (151; MTM, unpublished data), probably because both sexes benefit from reuse of a former territory (24).

Extra-Pair Copulations

Never observed, but because frequency of extra-pair paternity so common, must occur regularly. Neither within-pair nor extra-pair copulations seen during the day. Given that males are virtually always on their territory singing in the darkness of the Dawn Song period, it must be the female that moves about in the predawn darkness to locate and copulate with extra-pair males.

Social and Interspecific Behavior

Degree of Sociality

Solitary in early breeding season, tolerating only opposite-sex individuals. Other nesting passerines frequently attacked when they approach nest tree (4, MTM). As season progresses, tolerance increases steadily until other kingbirds and even other family units tolerated. Very social during migration and in South America. Autumn migrating flocks sometimes number in thousands, and during the overwintering period, flocks of 10–20 individuals may forage together (103, 80). Large night time roosts occur in nonbreeding season (R. D. Renfrew, personal communication).


Not known to occur.

Nonpredatory Interspecific Interactions

Interactions with other species minimal. May nest in close association with Orchard Oriole (Icterus spurius; 98), Baltimore Oriole (I. galbula; MTM), American Robin (Turdus migratorius; MTM), Cedar Waxwing (Bombycilla cedrorum; 111), Tree Swallow (Tachycineta bicolor; M. Funk, personal communication), and other kingbird species (152, 153), because all are attracted to the same nesting sites. Has been observed nesting near nests of Swainson's Hawk (Buteo swainsoni) or Ferruginous Hawk (B. regalis), possibly because hawks prey on nest predators (153). A report of a female Eastern Kingbird feeding nestling Baltimore Orioles probably represents misdirected parental care in female that lost nestlings (154). Will usurp nests of Baltimore and Bullock's (Icterus bullockii) orioles prior to the oriole laying eggs (MTM), and in eastern Oregon regularly reuses old nests of mainly American Robins, but also Brewer’s Blackbird (Euphagus cyanocephalus) (155).

Tends to be dominated in South America by other frugivores (103). Flocking may prevent territorial frugivores from excluding this species from fruiting trees. Often seen foraging with Tropical Kingbird (T. melancholicus) or Fork-tailed Flycatcher (T. savanna) in South America (70, 71).


Kinds of Predators

Relatively few predators on adults, probably mainly accipiters and falcons (for other kingbirds see 143). American Kestrel (Falco sparverius) may occasionally depredate nestlings, fledglings, and possibly adults; one kestrel was observed to lift an Eastern Kingbird from the back of a Red-tailed Hawk (Buteo jamaicensis) that the kingbird was harassing (J. Rivkowich, personal communication). Other common predators of eggs and nestlings vary geographically. In the East, predators include Blue Jays (Cyanocitta cristata), American Crows (Corvus brachyrhynchos), and squirrels (Sciurus spp.) (9, 7). Tree-climbing snakes are important where abundant (e.g., Kansas; 10, 11), and in the West, Black-billed Magpies (Pica hudsonia) and American Crow are probably important nest predators (25, 116).

Manner of Predation

Successful depredation requires a surprise attack.

Responses to Predators

Attacks by Eastern Kingbirds on nest predators such as corvids, raptors, and even large, nonpredatory birds are legendary (4, 29), and aggressiveness increases the chances that an active nest will fledge young (156; but see 25). Individual variation in male nest defense behavior repeatable (i.e., individuals are consistently either more or less aggressive; 25). Unsuspecting Blue Jays have been knocked out of trees or driven to ground to seek shelter under bushes (MTM). Flying crows, all Buteo hawks, Northern Harrier (Circus hudsonius) and basically all raptors are attacked whenever they enter kingbird's defended space (except when kingbirds nest close to hawks; see Social and Interspecific Behavior). Eastern Kingbird will attack squirrels or Long-tailed Weasel (Mustela frenata) by darting quickly in and out of vegetation to drive predator from nest vicinity (MTM). Attack intensity does not differ between incubation and nestling periods (157, 25), but both eggs and young are defended more aggressively than empty nests (157). Repeated presentations of taxidermic mounts lead to habituation and less intense response (157).

May expose and raise red crown feathers during attacks. Also uses particularly startling display during vigorous attacks on humans and presumably other predators. While in steep dive toward predator's head, an Eastern Kingbird may expose and raise red crown patch and open mouth wide to reveal red gape. The effect is dramatic and has caused at least one human to nearly lose his grip and fall from a tree (MTM).

Responses to predators on adults vary. Flying accipiters that have been spotted are chased (158, 143, MTM). American Kestrels also chased, but kingbirds seem to give them wider berth (MTM).

Recommended Citation

Murphy, M. T. and P. Pyle. 2018. Eastern Kingbird (Tyrannus tyrannus), version 2.0. In The Birds of North America (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.