Endangered gulls found dead on one of Scotland’s most important seabird islands, in the Firth of Forth, have tested positive for avian flu.
The great black-backed gulls were sent for tests last month after eight were found dead on the Isle of May.
It is the first time the deadly H5N5 strain has been recorded on the island, which is a national nature reserve (NNR) run by NatureScot.
The great black-backed gull is the world’s largest gull with a wingspan up to 1.7 metres.
It was recently added to the UK Red List of Birds of Conservation Concern. The Scottish population has declined by 63% since 2000.
Species on the Isle of May including kittiwakes, guillemots and Arctic terns have suffered from the Highly Pathogenic Avian Influenza (HPAI) H5N1 in recent years, but this summer the island was “bird flu free”.
David Steel, NatureScot’s reserve manager on the island, said: “In early October, eight Great Black-backed Gulls were discovered dead on Rona, the northern part of the Isle of May.
“This was unusual for the time of year and testing was undertaken. In recent days we’ve had it confirmed that the birds died of H5N5, a strain of bird flu which we have yet to record on the island…
“If there is one saving grace, at least this is not the breeding season where birds would have close contact and spread the virus quickly. Hopefully this is an isolated incident and we hope to have a trouble-free winter and then another clean summer.”
Mark Newell, UK Centre for Ecology & Hydrology (UKCEH) field manager on the island, said: “At this stage of the season, during winter, the risk to most of the seabirds we study is low because most species, including kittiwakes, guillemots, razorbills and puffins, are away from the island.
“However, there are large numbers of gulls — herring gulls and great black-backs — present on the island at this time of year, as well as European shags and cormorants, so there may be a risk to these species.
“Gulls in particular roost on the island at high densities, of a few thousand birds. It is not surprising that cases in gulls have occurred on the Isle of May.
“Although previous cases on the Isle of May have been H5N1, there have been records of a variety of species testing positive for H5N5 throughout the UK, including herring gulls, great black-backed gulls and also a cormorant, with cases in Fife, close to the Isle of May.”
A NatureScot spokesperson said: “Over the past few months, there have been a number of positive cases of avian flu detected in wild birds in Scotland. These cases have mainly been in the Northern and Western Isles, but there have also been positive findings in the Highlands and in Fife and East Lothian.”
The spokesperson added: “In contrast to recent years, the findings in Scotland this year have all been the H5N5 strain of the virus, rather than H5N1. As a result of the latest findings, the risk of avian flu in wild birds in Great Britain has increased from medium to high.”
