Opinions and declarations Rendered by the International Commission on Zoological Nomenclature

The swiftlets (Aves, Apodidae, Collocaliini) have been known as producers of edible nests for four centuries. Among the genus Aerodramus Oberholser 1912 ecological evidence and museum specimens support the existence of two wild species making ‘white’ edible nests: grey-rumped swiftlet Aerodramus inexpectatus (Hume, 1873), a species occurring on islands, rocky stacks and maritime cliffs from the Andaman Islands to the north-east coast of Borneo, and brown-rumped swiftlet A. fuciphagus (Thunberg, 1812), occurring at inland sites only in Borneo, but at inland and island localities in Sumatra, Java, and Nusa Tenggara Barat, Indonesia. Housefarm swiftlets, which make similar white nests, were first recorded as spontaneous occupiers of buildings in Java, Indonesia, in the late 19th century, presumably from A. fuciphagus stock. In Peninsular Malaysia and Singapore, the first observations of nesting in buildings were made later, from 1931 to 1947. Subsequent human intervention has greatly expanded the numbers and range of house-farms, first in Java and elsewhere in Indonesia by fostering eggs in the nests of Linchi Swiftlets Collocalia linchi, and latterly by the use of recorded vocalisations to attract birds into purpose-made buildings. During the 20th and early 21st centuries, house-farm swiftlets and ‘house-farming’ have largely replaced wild colonies as sources of white nests. Previous genetic evidence based on mitochondrial DNA (mtDNA) has supported species level separation of the two wild white-nest species but more recent genetic studies have questioned this conclusion. The present study has focused on mitochondrial genetics with new samples of swiftlets from house-farms in Peninsular and Bornean Malaysia, and wild grey-rumped swiftlets Aerodramus inexpectatus on the islands of Mantanani Besar, Sabah, and Seringgis, Terengganu. GenBank data were used to extend comparisons to include house-farm swiftlet mtDNA from southern Thailand and Vietnam. Re-analysis of the three previous studies of genetic diversity in house-farm swiftlets coupled with the new supplementary data of mitochondrial cytochrome-b shows that the multiple maternal lineages observed within the house-farm swiftlets of Malaysia can also be detected more widely across the Southeast Asian region. In conclusion, we argue that housefarm swiftlets exhibit behavioural characters that could be considered evidence of domestication. We hope to see further studies using fuller genome sequencing to give improved insights into the phylogenetics of the progressive domestication of house-farm white-nest swiftlets.

The swiftlets (Aves, Apodidae, Collocaliini) have been known as producers of edible nests for four centuries. Among the genus Aerodramus Oberholser 1912 ecological evidence and museum specimens support the existence of two wild species making ‘white’ edible nests: grey-rumped swiftlet Aerodramus inexpectatus (Hume, 1873), a species occurring on islands, rocky stacks and maritime cliffs from the Andaman Islands to the north-east coast of Borneo, and brown-rumped swiftlet A. fuciphagus (Thunberg, 1812), occurring at inland sites only in Borneo, but at inland and island localities in Sumatra, Java, and Nusa Tenggara Barat, Indonesia. House-farm swiftlets, which make similar white nests, were first recorded as spontaneous occupiers of buildings in Java, Indonesia, in the late 19th century, presumably from A. fuciphagus stock. In Peninsular Malaysia and Singapore, the first observations of nesting in buildings were made later, from 1931 to 1947. Subsequent human intervention has greatly expanded the numbers and range of house-farms, first in Java and elsewhere in Indonesia by fostering eggs in the nests of Linchi Swiftlets Collocalia linchi, and latterly by the use of recorded vocalisations to attract birds into purpose-made buildings. During the 20th and early 21st centuries,house-farm swiftlets and ‘house-farming’ have largely replaced wild colonies as sources of white nests. Previous genetic evidence based on mitochondrial DNA (mtDNA) has supported species level separation of the two wild white-nest species but more recent genetic studies have questioned this conclusion. The present study has focused on mitochondrial genetics with new samples of swiftlets from house-farms in Peninsular and Bornean Malaysia, and wild grey-rumped swiftlets Aerodramus inexpectatus on the islands of Mantanani Besar, Sabah, and Seringgis, Terengganu. GenBank data were used to extend comparisons to include house-farm swiftlet mtDNA from southern Thailand and Vietnam. Re-analysis of the three previous studies of genetic diversity in house-farm swiftlets coupled with the new supplementary data of mitochondrial cytochrome-b shows that the multiple maternal lineages observed within the house-farm swiftlets of Malaysia can also be detected more widely across the Southeast Asian region. In conclusion, we argue that house-farm swiftlets exhibit behavioural characters that could be considered evidence of domestication. We hope to see further studies using fuller genome sequencing to give improved insights into the phylogenetics of the progressive domestication of house-farm white-nest swiftlets.