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Aerial, Extremely Fast, Summer Visitors… Swifts in Sydney

By Keith Hutton on January 10, 2012 in Other

Photo: Rohan Clarke

There are over ninety species of swifts worldwide but they are not well represented in mainland Australia, where only three of them occur regularly. Two of these migrate to Australia following breeding in Asia, and both can be seen in the eastern suburbs of Sydney in summer. Spine-tailed Swifts, now known as White-throated Needletails, have an eastern distribution whereas Fork-tailed Swifts occur throughout Australia with a preference for the drier regions and the west. Both visit Sydney annually between October and April. The third species, the Australian Swiftlet, is restricted to the tropical lowlands of northeast Queensland.

Swifts superficially resemble swallows and martins but they are not closely related to them and behave very differently. They are extremely fast fliers and appear stiff and mechanical in flight. Swifts are almost exclusively aerial and adapted to long periods in the air. Their long, narrow, backswept wings allow effortless gliding as well as exhilarating speed, with sharp changes in direction. White-throated Needletails are bigger than Fork-tailed Swifts, appear more powerful and have a short rounded tail. They have a white forehead, throat and under tail, and a brown back and rump. Fork-tailed Swifts have long, slender, curved wings, a cigar-shaped body and a long forked tail. They appear more buoyant in flight and are mostly sooty except for an indistinct pale throat, and above they have a pure white rump.

White-throated Needletails occur over most types of habitat but probably more often over open forest areas. Fork-tailed Swifts are seen mostly over inland plains and in coastal areas over cliffs and beaches. I was surprised to be entertained by a small group of thirty or so Fork-tailed Swifts screaming excitedly, flying low over Magic Point at Maroubra a few years ago at around midday, late December, in hot and sultry conditions with masses of cumulus clouds. Behaviour of swifts is strongly influenced by the weather. They appear to favour areas with low-pressure systems, sometimes in large flocks, soaring and wheeling and dashing about in their search for food.

Flying insects such as ants, termites, bees, beetles, grasshoppers and airborne invertebrates like drifting spiders are all acceptable food items. Swifts feed in mixed flocks with other aerial foragers, often in rising air before thunderstorms and around bushfires, near the ground or high in the sky, scooping prey into wide, gaping mouths.

Flocks of 50 to100,000 birds have been recorded in Australia for both species of swifts that visit Sydney, but there are no measures of overall abundance for either. Both may collide with overhead wires, windows and lighthouses and be killed during migration, but there is no evidence that these collisions are affecting overall numbers. The most recent surveys suggest that there has been a decline of more than 20% in numbers of White-throated Needletails in Australia, but this probably reflects new recording methods, which are less likely to pick up swifts, rather than a real change of conservation status.