Pacific Swift

The Pacific swift (Apus pacificus) is a bird of remarkable aerial prowess, belonging to the Swift family. It is the largest of the Apus swifts, measuring 17–18 cm in length with a wingspan stretching between 43 to 54 cm. This species exhibits a blackish plumage with a distinctive white rump band and heavily marked underparts, which sets it apart from its relative, the common swift. Both sexes are identical in appearance, but the younger birds can be discerned by the pale fringes on their wing feathers, which adults lack.

Identification Tips

When identifying the Pacific swift, look for its long wings, protruding head, and deeper tail fork compared to the common swift. The upperparts are black, save for the white rump band and a greyer head. The underparts are also black, but the white feather fringes give the belly a scaly look when viewed from below. The southern subspecies, A. p. kurodae, is distinguishable by a narrower white rump and darker underparts.

Habitat

Pacific swifts are found across a broad spectrum of climatic zones and habitats. They breed in protected areas such as caves, natural rock crevices, or under house roofs. During winter, they are typically found in lowlands and, in Australia, inhabit arid regions as well as urban and coastal areas.

Distribution

This species breeds in eastern Asia and is a strong migrant, wintering in Southeast Asia and Australia. The Pacific swift has a vast breeding range, from the Ob River northeast to Kamchatka and east to the Kuril Islands, Sakhalin, and Japan. It has been recorded as a vagrant in locations as distant as the US and New Zealand.

Behaviour

The Pacific swift is a colonial nester, preferring sheltered sites for breeding. It constructs a half-cup nest of feathers and grass, cemented with saliva. The two or three white eggs laid are incubated for about 17 days, with chicks fledging after an average of 40.5 days. This swift is known to sleep in flight when not nesting, a behavior also suspected in other Apus species.

Song & Calls

The Pacific swift's vocalizations are typical of its family, with a trilled tsiririri or a harsher spee-eer call. These sounds are softer and less wheezy than those of the common swift.

Breeding

The Pacific swift breeds in colonies, with nests made of feathers and grass, glued together with saliva on ledges or vertical surfaces. Clutch size varies geographically, with two to three eggs being the norm. Both parents share incubation duties, and the altricial chicks are brooded and fed until they fledge.

Diet and Feeding

This swift exclusively feeds on insects caught mid-flight, such as bees, wasps, termites, moths, and flies. It hunts at higher altitudes than most of its relatives, often near low-pressure areas that lift insects from the ground and provide additional lift for the birds.

Conservation status

The Pacific swift is classified as Least Concern by the International Union for Conservation of Nature (IUCN). It has a large population and extensive breeding area, with few threats from predators or human activities.