Tree Swallow

Taxonomy/Description

The Tree Swallow is a member of the order Passeriformes, which consists of perching birds. It is a member of Hirundinidae, the swallow and martin family. The species modifier, bicolor, translates as “two colors,” a reference to the two solid, contrasting colors of its back and belly.

A Tree Swallow measures 5-6 in from head to tail (12-15 cm). Wingspan measures 12-14 in (30-35 cm). A Tree Swallow weighs between 0.56 and 0.88 ounces (16-25 g). There is a small fork present in the tail. Both male and female Tree Swallows have a dark blue-green back and a pure white belly. Juveniles have a grayish brown back with a dull white belly.

Habitat/Diet

The summer range of the Tree Swallow extends from the central portions of the United Sates up through Alaska and throughout Canada. Their winter range runs from the southern portions of the United States to Central America. Tree Swallows can be found in open lands near water. They live in places such as meadows, marshes, grasslands, wooded swamps, shorelines, and rivers.

Tree Swallows are aerial insectivores. They forage for flying insects, such as mosquitoes, while in flight, but they also search the ground for other insects and spiders. Tree Swallows also occasionally eat berries and seeds.

Behavior/Reproduction

Tree swallows are polygamous. They live in loose colonies, where the males maintain small territories. Males arrive at the breeding ground a week before the females do in order to establish these territories. Males may flutter, bow, or sing to attract females.

The nest is made by the female, although the male may help to gather materials. The nest is a cup shaped structure made out of grasses and pine needles. Tree Swallows roost in snags, or dead standing trees, nest boxes, and tree cavities. Female Tree Swallows lay between two and eight eggs. Females are the only incubator, and they have been known to abandon their nests for a few days. After two weeks, the eggs hatch. Both parents feed the young until they fledge, which can be anywhere from sixteen to twenty-four days.

Vocalization

Tree Swallow songs are a series of liquid twittering that resemble the sound of a bubbling brook.

Where to see them in WNY

Tree swallows are found in open meadows, near rivers and lakes, and also in marshes. A good place to find them is the Iroquois National Wildlife Refuge.