Vaux’s Swift, a Sign of Spring

by Vick Applegate…

For many of us, certain sights or sounds signal the return of spring. For me, it’s the song of an early morning robin, the call of geese on their northern migration, the appearance of buttercups or the first sound of my neighbor’s lawn mower. More recently spring is the arrival of flying house guests.

For the last six-years our sign of spring is the predictable arrival of Vaux’s swifts (Chaetura vauxi) to our fireplace chimney. Returning from Central America or Mexico every May 1, within a day or so, 5-10 swifts arrive resonating a noisy high-pitched chirping from our chimney. There they roost for several nights to a week or more before they disperse except for a pair or two that remain to nest in the chimney.

Vaux’s swifts are the smallest swift of North America and are most closely related to hummingbirds. They are primarily a forest species in the West whose habitat for roosting and nesting is hollow trees with vertical entrances. Swifts roost in a vertical position, grasping with their tiny legs the inside of trees or at our house, the inside of the brick chimney. In Western Montana common roosts and nests are in large old grand fir and lesser amounts of western larch and western redcedar with broken tops. Birder observations indicate that Vaux’s swifts may be moving into man-made structures like chimneys due to a loss of suitable trees.

David Sibley’s Guide to Bird Life and Behavior and the Cornell Lab of Ornithology’s All About Birds say that swifts do almost everything ‘on-the-fly’. They feed on insects and spiders, drink water, gather nest materials, and even mate in the air. They build their nests by cementing twigs together with a sticky saliva mix. (The famous Chinese cuisine, ‘bird’s nest soup’, is prepared from saliva-made nests of mainly two Asian swiftlets: Aerodramus fuciphagus & maximus).

In our chimney, we cannot see the nest building. The swifts remain fairly quiet until the young hatch. But by July, the peeping sounds of young swifts resonate into our living room as they compete for food ferried to them by their parents. The feeding flight is pretty amazing, a chirping announcement of their arrival, a rapid beating of their wings, a quick circling and then a diving or fluttering controlled-plummet into the chimney. The noise becomes increasingly intense until the young fledge. After fledging they regroup nightly to roost and their noisy ‘feed me’ chatter is replaced with a much lower-volume ‘welcoming’ sound from roosting birds. There is also a low-pitched rumble from the fireplace as each fly up out of the chimney every morning. Then one-day after mid-summer it’s full silence, our fun watching them is over and they’re gone until next spring. Soup anyone?


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