Nature Notes

A bird perched on a wire can be iconic, or a cliché. But what bird it is? The eastern kingbird (Tyrannus tyrannus) is one such bird that you might recognize fairly easily. It’s a flycatcher that migrates from the Amazon area in South America to breed here, and then returns there in the fall.

What makes this kingbird recognizable? The white band at the tip of its tail is the key. You can spot the white-tipped tail in both front and back views of the kingbird. Overall, the bird is mostly dark, with a black head and gray-black back, wings, and tail, and with white underneath.

Why is this bird called a king? The name comes from the bird’s habit of being aggressive, even tyrannical, in defending its breeding territory and airspace. The eastern kingbird is only about the size of a robin (7-9 inches long), but you might see a lone kingbird vigorously chasing off a much larger red-tailed hawk, or any bird of prey, or even a squirrel, especially during the nesting season. Maybe you’ve seen a group of crows or blue jays mobbing a hawk, but a kingbird will turn the tables and attack a crow or blue jay that ventures too close. Eastern kingbirds also don’t like others of their own species near their territory. Their nature is also recognized by a double “tyrant” in their scientific name Tyrannus tyrannus, which dates from 1799.

This little king doesn’t exactly have a crown, but when in pursuit, it can raise small red feathers in a crest on its head. This red isn’t easy to see, however.

Besides telephone wires, kingbirds also perch on fences and tops of shrubs or trees. Look for them in open areas, such as fields and woodland edges. They build bulky cup nests in trees, often near water, as in our photo. These areas are all places where a flycatcher can find insects and maneuver to capture them in the air.

Flycatching is a widespread and venerable profession among birds. The eastern kingbird is one of a more than 400 species in the Tyrant Flycatcher family of birds in North and South America, but only a few breed in North America. Eastern kingbirds prefer large insects, such as dragonflies, butterflies, grasshoppers, beetles, and bumblebees. These kingbirds perch and watch for flying insects, and then fly out to snatch their food from the air. They typically return to their perch to swallow a captured insect whole. You might be familiar with flycatching from seeing other birds, such as phoebes, fly out from a branch to catch smaller insects in mid-air. Other flycatchers in our area include wood-pewees, great-crested flycatchers, willow flycatchers, least flycatchers, and more.

Insects are the main food for kingbirds during their spring migration and the breeding season, but they also eat some wild fruit, especially as berries ripen throughout summer and into fall. Kingbirds eat mainly fruit on their South American wintering grounds.

What about sounds? Eastern kingbirds are relatively quiet, so they’re not the easiest birds to find by ear. Listen for short buzzing sounds and then look around for a kingbird. Their sounds are determined by genetics, not by learning from listening to parent birds.

Eastern kingbirds typically arrive in our area in late April or the first week of May. The male and female of a pair migrate separately and don’t stay together on their South American wintering grounds. In spring, they meet up again in the same place where they’ve bred before. They nest promptly, raising 3-4 chicks, which the parent birds keep on feeding for 3-5 weeks after the chicks have left the nest. Kingbirds leave our area from late July through September. Their aggressiveness wanes as the breeding season ends. In late summer, you might spot a whole flock in a coastal area before the birds head out over water.

How do these birds manage to navigate back to the same place to breed each year? Many birds do similarly, but how they do so is not well understood. Possible explanations are controversial. Birds may be able to sense and remember patterns of magnetic fields, which vary considerably over the earth. Such a magnetic sense might involve the mineral magnetite and special receptors around a bird’s beak. Another possibility may involve a bird’s eyes, especially photopigments that respond to both light and magnetic fields, such as one called cryptochrome, which is affected by blue and turquoise light.

How are eastern kingbirds faring these days? Kingbirds are basically grassland birds that need insects. Breeding bird surveys show that eastern kingbird numbers have declined by at least 40 percent since 1966. In our area – their breeding grounds – a possible reason is habitat loss as forests have grown back in Massachusetts since the heyday of agriculture in the 1800s. Another reason may be the decline of insects due to widespread pesticide use.

Enjoy looking and listening for kingbirds this season, and again next spring. While you’re at it, you might also see other black birds alone or in flocks on the wires, such as European starlings (Sturnus vulgaris), common grackles (Quiscalus quiscula), red-winged blackbirds (Agelaius phoeniceus), or brown-headed cowbirds (Molothrus ater).