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Cassin's Kingbird Life History


Open Woodlands

Cassin’s Kingbirds occupy a great array of habitat types stretching from southeastern Montana to Nicaragua. Most of these habitats combine tall trees for nesting and open spaces for flycatching. In the western U.S., look for this species in open woodlands along canyons, rivers, and streams at lower and middle elevations, along with agricultural areas, grasslands, oak woodlands, oak savanna, pine woodlands, and pinyon pine-juniper scrubland. Migrants often forage in open country from utility poles and wires or other human-made structures. In central and southern Mexico, where this species is a permanent resident, it inhabits everything from lowland thorn forest to pine-oak forest at over 9,800 feet elevation.

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Cassin’s Kingbirds eat mostly insects captured in flight, along with small amounts of fruit. They hunt visually from an elevated perch, often a dead branch in a prominent tree, sallying out to take insects in midair with a quick snap of the bill. Like other kingbirds, they also pick insects, especially caterpillars, from the ground or from vegetation. Prey includes beetles, bees, wasps, ants, flies, aphids, leafhoppers, cicadas, grasshoppers, crickets, bugs, moths, butterflies, dragonflies, and spiders. When ripe berries such as grape, elderberry, or blueberry are available, Cassin’s Kingbirds may eat large quantities of fruit as well.

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Nest Placement


Nests are set in the upper third of a tall tree, usually in the outer portion of the tree on a horizontal branch.

Nest Description

Females construct a bulky nest of twigs, bark, roots, leaves, and other plant matter (sometimes with twine or other discarded material). They line the nest with finer plant matter such as grasses and rootlets. Some nests are adorned with feathers or flowers. Nests average about 8 inches across and 3 inches tall, with interior cup about 3.5 inches across and 2 inches deep.

Nesting Facts

Egg Description:

Eggs are creamy white with small brown spots.

Condition at Hatching:

Naked, helpless, eyes closed.

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At the beginning of the breeding season, males establish and defend territories that include at least one primary feeding site, usually a tall tree appropriate for hunting and often for nesting. Males are vocal, even at night, and often begin a dawn song around 3:00 a.m. During the day, probably to mark territories, they call loudly as they fly sharply upward, stop, and then fall in a tumbling, twisting flight. In larger territories, males make regular flights around the territory and drive away rivals, sometimes preceded by a threat display in which both males crouch, droop the wings, and flick the tail. Where pairs nest closer together, males rarely patrol the area but instead remain near the nest tree and call in response to other calling males in the area. As with other kingbirds, male and female Cassin’s greet each other excitedly by calling, fluttering the wings, and spreading the tail. Females build the nest and incubate the eggs; males forage and watch for predators from a nearby perch. Both sexes feed the nestlings.

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Low Concern

According to the North American Breeding Bird Survey, Cassin’s Kingbird populations were stable between 1968 and 2015. Partners in Flight estimates a global breeding population of 8.8 million and rates the species a 9 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. A 2016 Partners in Flight report estimates the U.S. population at about 2.6 million breeding individuals. Habitat loss, including the removal of individual large trees that the birds use for nesting and perching, is the chief conservation concern.

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Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Rosenberg, K. V., J. A. Kennedy, R. Dettmers, R. P. Ford, D. Reynolds, J. D. Alexander, C. J. Beardmore, P. J. Blancher, R. E. Bogart, G. S. Butcher, A. F. Camfield, A. Couturier, D. W. Demarest, W. E. Easton, J. J. Giocomo, R. H. Keller, A. E. Mini, A. O. Panjabi, D. N. Pashley, T. D. Rich, J. M. Ruth, H. Stabins, J. Stanton, and T. Will (2016). Partners in Flight Landbird Conservation Plan: 2016 Revision for Canada and Continental United States. Partners in Flight Science Committee.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Tweit, Robert C. and Joan C. Tweit. (2000). Cassin's Kingbird (Tyrannus vociferans), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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