Aberdeen University team identify Tern as distinct seabird species

A threatened seabird has been identified as a distinct species by new research, potentially having an impact on its conservation status.

The West African royal tern was previously considered to be the same species as the American royal tern.

However, scientists at the University of Aberdeen have used DNA analysis to show the “maximus” bird found in the Americas and the “albididorsalis” in parts of West Africa are not subspecies of the same bird but two distinct species.

Researchers said the discovery could have immediate conservation consequences for the West African royal tern as its population is threatened by the eroding of its breeding grounds due to climate change and human activity.

They have also shown the bird is more closely related to the lesser crested tern, which is a lot smaller and has a yellow bill.

Professor Martin Collinson, from the university's institute of medical sciences, said: “West African and American royal terns have long been considered the same species.

“They look pretty much identical to each other, except the American royal tern is on average slightly bigger with a slightly redder bill.

“This research should have an impact on the West African royal tern's conservation status. The breeding grounds in the Gambia and Senegal have been massively eroded by storms and the encroaching human population, so the West African royal tern is under threat.

“Conservationists in the Gambia can now take this information to their government and potential donors, and call for help to protect this West African endemic species.”

Scientists at the university, in collaboration with those at the universities of Montpellier and Hull, made the discovery by analysing DNA sequences of feathers and other remains of West African royal terns from Mauritania and from islands off the Tanji Bird Reserve in the Gambia.

The process allowed them to compare a bird's DNA sequence with every other bird that has been studied in this way using online tools, with software able to establish a bird's closest matches.

The resulting search revealed the West African royal tern's nearest relative was not the American variant, but the lesser crested tern.

It is the first time anyone has ever sequenced the DNA of the West African royal tern, the University of Aberdeen said.

Prof Collinson added: “It's information that can inform conservation priorities. There is a limited pot of money and information such as this helps determine where it should be allocated.

“It is important to direct conservation funds to preserve the maximum amount of genetic variation and genetic biodiversity, in addition to understanding the inherent societal, cultural and economic importance of the birds themselves.”

The findings have been published in the Biological Journal of the Linnean Society.