Vaux's Swift

The Vaux's swift, a diminutive member of the Chaetura genus, is a bird that captures the essence of the sky. With a length ranging from 10.7 to 11.5 cm and a weight of a mere 18 grams, it is a marvel of avian design. Its body is cigar-shaped, complemented by crescentic wings and a short, bluntly squared-off tail. The plumage is a dusky black across the head, upperparts, and wings, while the underparts, rump, and tail coverts are a more subdued greyish brown. A paler grey throat, which can appear almost whitish in northern birds, distinguishes it from its relatives. Both sexes share this coloration, though juveniles can be identified by dusky bases to their throat feathers.

Identification Tips

When observing Vaux's swifts, look for their characteristic rapid and erratic flight pattern, a mixture of stiff wing-beats and unsteady glides. Their small size and dark coloration are key identification features, along with their short, squared tails and the paler grey of their throats.

Habitat

Vaux's swifts are inhabitants of old growth forests, where they can be found flitting through coniferous or deciduous trees. These forests provide the large, hollow trees essential for their nesting.

Distribution

From the highlands of southern Alaska to central California, and from southern Mexico to northern Venezuela, the Vaux's swift is a bird of the Americas. The populations in the United States are migratory, wintering in central Mexico and throughout Central America, while those in the southern range are more sedentary.

Behaviour

These swifts are sociable creatures, often seen in flocks of 30 or more. They are known to mingle with other swift species, particularly at weather fronts. Their calls are more varied than their congeners, consisting of a symphony of chattering, buzzes, squeaks, and chips.

Feeding

In a dazzling aerial display, Vaux's swifts capture flying insects mid-flight. Their diet includes beetles, wasps, termites, and flying ants, and they forage over both forests and urban areas.

Breeding

Breeding takes place in the mountains and foothills, with nests built above 700 meters. The swifts construct a cup nest of twigs and saliva on vertical surfaces in dark cavities, laying three white eggs between March and July. During the winter, they retreat to the tropics.

Nesting

The nesting sites of Vaux's swifts are a testament to their ingenuity. They craft saucer-shaped nests from twigs or needles, adhering them to the inner surfaces of hollow trees or chimneys, strategically placed well above the cavity's base.

Subspecies

Seven subspecies of Vaux's swift are recognized, each with its own geographic range, from Northern Venezuela to Western Canada. The ashy-tailed swift, formerly considered a subspecies, has recently been acknowledged as a distinct species.

Conservation status

The IUCN Red List categorizes the Vaux's swift as Least Concern, indicating a stable population. However, the loss of natural roosting habitats, such as old growth Douglas-fir and forest snags, has led to adaptations such as the use of man-made structures for roosting.

Similar Species

While similar in appearance to other swifts, the Vaux's swift can be distinguished by its smaller size, specific call notes, and the paler grey throat.

Diet and Feeding

The Vaux's swift sustains itself on a diet of flying insects, which it captures with remarkable agility in the air. It forages in a variety of environments, from dense forests to open urban spaces.

Swifts at Chapman Elementary School

A notable phenomenon occurs at Chapman Elementary School in Northwest Portland, Oregon, where a migratory population of Vaux's swifts, known locally as "Chapman swifts," roosts in an old brick chimney. This event, occurring from mid-August to mid-October, attracts thousands of swifts and human spectators alike. The swifts' dramatic descent into the chimney at dusk is a spectacle not to be missed, and it serves as a reminder of the importance of preserving such unique natural occurrences.