Tree Swallow

The Tree Swallow is a common sight in open fields, meadows, marshes, ponds, lakeshores and other wetland areas where it uses its aerial acrobatics to feed on the wing. It is especially adapted to its incredible aerial life by being slender and sleek. Tree Swallows breed north to Alaska, across Canada, south and across the mid United States to North Carolina. It winters on the coasts of southern US, Central America and Islands in the Caribbean

Adult Male (spring/summer)

Sharp contrast on side of head: glossy, iridescent blue-green above a thin black eye mask and white below. White cheek patch does not extend above the eye. Chin, breast, belly and undertail coverts are white. Glossy blue-green extends down nape and back. Wings and tail are black. Legs are shore and feet are small and week.

Adult Female (spring/summer)

Duller than adult males but some older females show some iridescence.

Juvenile

Uniform gray-brown on head and back. White tips on tertials. Sharp contrast on sides of heads: white and gray brown. Chin is white; pale grayish breastband on white breast. Belly and undertail coverts are white.

General:

Stocky, broad winged swallow. Length: 12-15cm. Wing: 30-35cm. Weight: 16-25grams.

Behaviour:

Watch the Tree Swallow darting, gliding and using abrupt turns feeding in flight from dawn till dusk on insects. And observe them perched in flocks in long rows on branches and wires.

Habitat:

Open areas usually near water, including fields, marshes, shorelines and wooded swamps with standing dead trees.

Information:

During migration Tree Swallows gather in large roosts at night. They are diurnal migrants flying low to very high in loose flocks. Unlike other swallows, this species can subsist for extended periods on seeds and berries allowing some coastal populations to winter as far north as Long Island. A hole nester, the Tree Swallow depends on woodpeckers and other species that excavate and abandon cavities in dead trees, and to a lesser extend on nest boxes, which it accepts readily to lay 4-6 white eggs.

Similar species:

Barn Swallow, Cliff Swallow, Violet-green Swallow, Northern Rough-winged Swallow

Conservation Status:

Listed as Least Concern. Over the past 25 years populations have increased in eastern and central regions and across the continent. However, Tree Swallows are vulnerable to habitat destruction and pollution in wintering and breeding areas.

Although the most plentiful swallow around the banding station and breeding in the direct vicinity, as an aerial insectivore, Tree Swallows are difficult to capture as is reflected by generally low capture rates. Capture rates do indicate however Tree Swallow presence from March through July and peaks in June as juveniles disperse. No captures from August to February reflect this long distant migrant’s movement south during the winter months.

Molt Summary:

PF: HY complete (Jul-Nov); PB: AHY complete (Jul-Nov); PA absent-limited

Spring/summer – Consider the body plumage:

If there is any brown on the head or back the bird is a female.

– >50% brown indicates a SY female
– 10-50% brown indicates an AHY female
– 1-10% brown indicates an ASY female

If the head and back are entirely green-blue it may be a male of any age or an ASY female

Check the flattened wing chord: <114 mm bird is a female >121 mm bird is a male

Variation in the back colour of Tree Swallow by age and sex.

Adults like this bird in May have primarily or entirely uniformly bright iridescent blue upperparts including the forehead (see sexing above).

This AHY bird of unknown sex in May is showing worn primary coverts with iridescent blue lesser, median and greater coverts.