The welcome swallow (Hirundo neoxena) is a small passerine bird in the swallow family Hirundinidae that is native to Australia and nearby islands. It has self-introduced into New Zealand in the middle of the twentieth century. It is very similar to the Pacific swallow with which it is often considered conspecific.
This species breeds in southern and eastern Australia in a variety of habitats, mostly in open areas, man-made clearings or urban environments, but not desert or dense forest. Eastern populations are largely migratory, wintering in northern Australia. Western birds and those in New Zealand are mainly sedentary.
Taxonomy
The welcome swallow was first described in 1842 by John Gould in his The Birds of Australia as a member of the genus Hirundo, but the first publication is often incorrectly given as in the Proceedings of the Zoological Society of London. Both its species name and common name refer to people welcoming its return as a herald of spring in southern parts of Australia. The welcome swallow is metallic blue-black above, light grey below on the breast and belly, and rusty on the forehead, throat and upper breast. It has a long forked tail, with a row of white spots on the individual feathers. These birds are about long, including the outer tail feathers which are slightly shorter in the female. The welcome swallow's weight is about 9-20g. From the Gould collection in Tasmania a "natural size" male had a wing size of , tail size of , and a culmen of . While the female has wings, a tail, and a culmen of . The call is a mixture of twittering and soft warbling notes, and a sharp whistle in alarm. However, their call is normally quiet and does not travel very far. Welcome swallows readily breed close to human habitation. Welcome swallows are commonly found on wires, posts and other perches.
Natural global range
Welcome swallows have a very large distributional range because they are a cross-regional species. This swallow species has been observed nesting in the majority of New Zealand and its surrounding islands, Australia and some parts of Tasmania. Currently, this species has been recorded in New Guinea, New Caledonia and other surrounding islands. The distribution of the welcome swallow also depends on seasonal change. During the winter, the welcome swallow in Australia will move towards the north which places it closer to the equator and warm weather. For the following spring, they will return to southern Australia to breed.
Behaviour
Breeding
thumb|Copulating welcome swallows
Once the welcome swallow reaches maturity it has a long breeding period. They have a monogamous social structure and a breeding period that lasts from August until March. Nesting sites can be a variety of areas and have been documented to be from urban and suburban areas to rural areas. Buildings, moveable boats and ferries, hollowed-out trees, caves and cliffs, mine tunnels and shafts, as well as underground water tanks have all been observed areas of nesting swallows. Eggs are generally laid in twenty-four- to forty-eight-hour intervals; however, one nest can have multiple clutches because the parent pair may abandon a nest if the clutch size is too small and then another pair will lay their eggs within that same nest. It is also believed that the swallow accumulates fat in order to survive time periods when food is scarce or conditions are bad. This method allows rapid growth when conditions are good and stable growth when conditions are bad. Especially in Australia, snakes are the most dangerous predator for the birds. Snakes can climb trees to reach the nests and eat the eggs or young birds. According to one New Zealand study, the only time a nest failed was from disturbing the nest during the incubation period; these instances were from humans, mammals such as mustelids, and blackbirds preying upon the eggs. Although no specific parasites were found, welcome swallows are known as colonial breeders and are at a high risk for parasites, which may be a cause of lower breeding success but an increase in immune responsiveness. This virus has two forms, cutaneous (mild harm) and diphtheritic (deadly); poultry is usually vaccinated for the virus, but wildlife is not.