Avian flu causes another challenging summer for seabirds

Avian flu causes another challenging summer for seabirds - NatureScot

two sandwich terns (black and white birds with pointed bills) adn one balck headed gull (grey and white bird with black cap All are on a sandy beach with some tussocky grass. — Sandwich terns and black-headed gulls at Forvie NNR ( © Lorne Gill/NatureScot)

Scotland’s seabirds faced another challenging summer as a result of avian flu, with auks, gulls and terns most affected.

Between 3 April and 1 October, NatureScot received reports of 9,610 dead and sick wild birds from sites across Scotland, with the majority of reports coming from locations along the east coast.

Following a quiet start to spring, a sudden increase in mortalities began in June and reached a peak in mid-July when around 2,300 sick and dead birds were reported in a two-week period.

The species with the highest number of reported mortalities were guillemot (3,519 birds) and kittiwake (3,367) followed by black-headed gull (834), herring gull (371), razorbill (368), common tern (304), Sandwich tern (231), Arctic tern (89) and other gulls (125). The remaining mortality sightings included 26 other species.

With many seabirds already experiencing multiple pressures and population declines, work is ongoing to assess the impact of avian flu and better understand why some species have been harder hit than others.

Guillemots, kittiwakes, and terns have experienced huge losses at their breeding colonies this summer, for example. On Forvie National Nature Reserve alone, more than 40% of this year’s Sandwich, common and Arctic tern chicks perished. A degree of natural mortality is normal among tern chicks, but the scale and sudden nature of avian flu related die-offs this past summer is unusual, and combined with the number of adult deaths reported, these losses are extremely concerning for the recovery of these long-lived birds.

RSPB Scotland have undertaken an enhanced programme of seabird monitoring this summer. The results will help indicate the extent of the impact on Scotland’s wild birds and are due to be published early next year. Early results for great skua, one of the species badly affected last year, show a drastic population decline of the breeding population at Hermaness NNR of 78%.

Scotland’s Avian Flu Task Force is now preparing for wintering waterfowl, with mortality surveillance shifting from seabird colonies to areas with high numbers of wintering species such as geese and swans.