Birds of the Glebe, Swallows

The iridescent blue feathers of the Tree swallow catch the light.
Photo: Jeanette Rive

By Jeanette Rive

Swallows are the small-winged acrobats, swooping and diving, chasing small insects. They are the aerial insectivores, a group of birds which includes swifts, flycatchers and Purple martins. Sadly, as with so many birds, their numbers have diminished over the last 50 years because of the decline of the insects they eat due to widespread use of insecticides in agriculture and domestic gardens. Environmentalists are pushing for much stronger regulations as these insectivores eat hundreds of insects a day.

The Tree swallow is the most common swallow around here, seen over waterways and ponds such as Brewer Park, where nesting boxes have been erected, and Dow’s Lake, where the Northern rough-winged swallow can also be seen.

Tree swallows in flight are wonderful to watch, their iridescent blue feathers catching the light as they swoop quite close to the surface of the water or fly as high as 50 metres in the air. Also, listen as they chirp while in flight! They can fly up to 45 km an hour to catch prey. They can even be playful, dropping a feather in mid-air and flying down to catch it – perhaps practising their skills. (The Peregrine Falcon is the world’s fastest bird, reaching diving speeds of 186 km an hour.)

Tree swallows are migrants, flying to Florida and Central America to winter. Unlike many birds, they migrate during the day, roosting in large flocks at night, causing a murmuration as they swoop around before landing in the trees. They winter further north than other swallows, living on bay berries when insects are not available. They are the first swallows to return around mid-April, coming back to the same nesting site every year. Choosing a new mate every spring, they are socially monogamous, though the male will venture elsewhere to mate with another female.

Tree swallows nest in cavities in trees, such as holes drilled by woodpeckers – their name comes from where they like to nest (though they also use nesting boxes!), just as Barn swallows get their name from nesting in barns. The male selects a site and shows it to his prospective mate, and there is often much competition to claim the best nesting spots. He initiates nest building by placing a bit of nesting material and some feathers, and the female completes the process. Four to six white eggs are laid – no colour needed to protect against predators because the nest is in a cavity and well-protected – and incubated by the female for 13 to 16 days. The eggs will hatch in the order they are laid. Both parents feed the babies, who leave the nest after about 20 days. The parents continue to feed them for another five to six days. There is only one brood a year.

How do you tell the difference between a swift and a swallow? Swifts fly higher than swallows, spend most of their lives airborne, are generally darker in colour (soft browns and greys) and their bodies are shorter and a bit plumper. But the main difference is that swifts cannot perch! If you see a bird perching upright on a nesting box, telephone wire or reed, it’s a swallow. Swifts have long claws which are only suitable for clinging to vertical walls inside chimneys or in hollow trees and caves.

For a close view of Purple martins, go to the Nepean Sailing Club where there is a martin house with about 96 nesting holes. The air around is filled with busy martins flying in and out feeding their young. They also arrive in April and leave around mid-August.

You may have read about the outbreak of Avian flu. It affects mostly waterfowl such as ducks, geese and some raptors, but some poultry farmers in the area have also had to cull their flocks. It is expected that the virus will fade over the summer, but it is recommended that feeders and bird baths be kept extra clean. If you see a goose or duck behaving abnormally, don’t call Safewings or the Wild Bird Care Centre – neither can accept them. Go to the Safewings website to learn about symptoms and, if necessary, the telephone numbers of the Canadian Wildlife Health Cooperative, which is monitoring the situation.

Jeanette Rive is a Glebe bird enthusiast and regular contributor to the Glebe Report.

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