Analysis of breeding data of the Welcome Swallow Hirundo neoxena near Manjimup, Western Australia

Abstract

Breeding data on the Welcome Swallow (Hirundo neoxena) collected by Dick and Molly Brown at the Middlesex Field Study Centre, near Manjimup, Western Australia, were analysed and compared with data from Sydney, Tasmania and New Zealand. The mean clutch size in Middlesex (3.06) was considerably lower than in Sydney (3.86), Tasmania (4.03) and New Zealand (4.49). The long, dry Western Australian summer and migration factors may account for the difference between Middlesex and Sydney but migration factors cannot account for those differences with New Zealand. Lack of competition in New Zealand, where the Welcome Swallow is a recent immigrant, may be the explanation for the differences. There was no correlation between latitude and clutch size from the four study sites. The hatching and fledgling success rates were noticeably higher in Middlesex than in the other three studies. Nesting sites close to water were preferred, possibly because they provided the birds with mud for nest building and a rich foraging place. Manmade nesting sites were used much more commonly than natural sites across all studies, perhaps because they were convenient and provide protection. There was no correlation between rainfall and breeding success. There was no evidence that pulli return to breed at the location in which they were reared.