Eastern Kingbird

Scientific Name	Tyrannus tyrannus
Survival Strategy	Long-distance Migrant/ Neotropical migrant
Arrival in Upper Midwest	May to early June
Departure	Early August to late September
Destination	South America (Brazil. Bolivia, Colombia, Ecuador)
Conservation Status	Least Concern

Phenology

Spring
The eastern kingbird returns to the upper Midwest in May to early June. Both male and female birds fiercely defend their territory. The female builds a nest of twigs, roots, and dry plant material, then lays 3 to 4 eggs. After 16 to 18 days of incubation by the female, the young hatch naked and blind (altricial).

Summer
The female broods her young for 16-18 days. After fledging, the young rely on both parents for food for about two weeks. The southward migration to the kingbird’s winter range begins in early August to late September

Fall
For most eastern kingbirds, the journey to the tropics includes crossing the Gulf of Mexico. They migrate directly to central Brazil, which is the southern edge of their winter range, to feed on the fruit of Yagrumo Macho trees.

Winter
As winter progresses, kingbirds work their way north, foraging on fruits in the tropical forest canopy of the western Amazon basin until April, when they begin their spring migration northward.

Behavior

Hunting
If the weather is favorable enough for insects to be flying, eastern kingbirds will use an aerial hawking feeding strategy, catching flying insects and eating them on the wing. Other times they will use a sallying approach, where they wait on a perch until they spot their prey, then fly quickly (sally) to grab the insect, then return to their perch before eating.

Physiology

Waiting Until Winter to Molt
Unlike many other birds, the eastern kingbird goes through only one yearly molt after it reaches its winter range in South America. This complete molt will replace every feather, although not all simultaneously. A kingbird can feed on fruit in the winter even while the molting of flight feathers temporarily reduces its aerodynamics. However, kingbirds are aerial insectivores in their breeding range and need all of their flight feathers to snag their fast-moving prey.

Diet

During the breeding season, the diet of the eastern kingbird is mostly flying insects such as flies, wasps, and bees, along with a few fruits in late summer. In their winter range, they feed primarily on fruits (frugivore), along with a few insects. Kingbirds cannot digest the exoskeletons of insects, so they must regurgitate pellets of insect chitin.

Lifespan and Mortality

The lifespan of the eastern kingbird has not been determined, although banding data suggest that two-thirds of adult eastern kingbirds survive annually. Most nestling deaths are due to nest predators.

Predators
American kestrels and merlins will prey on adult kingbirds, while blue jays, crows, and squirrels are nest predators.

Climate Vulnerability

In a warming climate, the range of the eastern kingbird will become slightly smaller and shift further north.

Never Stop Learning

Etymology: The genus and species of the eastern kingbird is Tyrannus tyrannus, which comes from Latin for “tyrant” and refers to a harsh ruler. The origin of the name is the same as the genus of a famous dinosaur with tiny hands, Tyrannosaurus rex.

References

Murphy, M. T. and P. Pyle (2020). Eastern Kingbird (Tyrannus tyrannus), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.easkin.01

Dewey, T. 2009. “Tyrannus tyrannus” (On-line), Animal Diversity Web. Accessed June 12, 2019 at https://animaldiversity.org/accounts/Tyrannus_tyrannus/

Boreal Songbird Initiative https://www.borealbirds.org/bird/eastern-kingbird

Yagrumo Macho https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/didymopanax/morototoni.htm

BirdLife International (2022) Species factsheet: Tyrannus tyrannus. Downloaded from http://www.birdlife.org on 28/01/2022

Cornell Lab of Ornithology, All About Birds, Eastern Kingbird http://www.allaboutbirds.org/guide/Eastern_Kingbird/lifehistory