​The small, streamlined body, tapering wings, and long, forked tail of the Welcome Swallow are adaptations to its aerial lifestyle, as this species forages almost entirely on the wing. Their flight is graceful and acrobatic, as they sharply turn, bank, and swoop to snap up flies, wasps, moths and other flying insects with their wide mouths. Unconstrained by the necessity to forage in trees or on the ground, Swallows may be found flying over most habitats, from grasslands to clearings in the forest. The Welcome Swallow has adapted very successfully to urban habitats, resting by day perched on power lines and buildings, and by night, roosting on ledges in covered or underground carparks. Some swallows have even learnt to take advantage of the large numbers of moths that are attracted to fluorescent lights in cities and towns by circling illuminated areas at night.

But the ability of Swallows to exploit urban environments is most obvious in their breeding behaviour, as nowadays they invariably build their mud nests on human-made structures, such as underneath the eaves, awnings or roofs of shops and houses, or under bridges, and even on boats. Yet before Europeans arrived and began constructing permanent buildings, Swallows presumably built their nests only in natural sites, such as cliff faces, underneath overhanging rocks, and inside caves or burnt out tree stumps, where some birds still nest.

Unlike the vast majority of urban-adapted birds, the Welcome Swallow is not always sedentary. In southern Australia, where temperatures in autumn and winter probably reduce the abundance of flying insects, many Swallows “disappear” in April or May, and do not return until late August. Indeed the name of the species, bestowed by the well-known naturalist John Gould over 170 years ago, refers to its return to southern Australia being a welcome indication of the approach of spring. Migratory individuals fly north as far as the Torres Strait in Far North Queensland, but others may just reach Brisbane, where they probably outnumber the resident birds for several months. One bird that was trapped in New South Wales, and marked with a numbered band on its leg, was re-trapped 8 months later in Western Australia, over 2,000 kilometres away, proving these tiny birds, weighing only 15 grams, are capable of flying long distances. Such scientific banding studies have also shown that this species can live at least 12 years.

Although usually in small flocks, Welcome Swallows may gather in larger flocks of many hundreds when roosting at night.

Text © Richard Noske 2019 CC BY-NC-SA