Research involving a colony of gulls on the Suffolk coast has shown the birds could be vulnerable to collisions with wind turbines while on migration, as well as during the breeding season.
The study conducted by the British Trust for Ornithology (BTO), which is based in Thetford, saw solar‐powered global positioning system (GPS) tags attached to adult lesser black-backed gulls at three breeding sites designated as Special Protection Areas.
They were Orford Ness, off the Suffolk Coast where 25 gulls were tagged, as well as South Walney in Lancashire and Skokholm, a small island of the coast of Wales.
The GPS devices recorded how fast and how high the birds fly, as well as the time birds spent in particular areas. By combining this data with information on wind turbine locations researchers were able to establish how vulnerable this species might be to collisions.
The results showed that lesser black-backed gulls are vulnerable during the breeding season, when birds are tied to feeding areas close to their colonies, many of which are also in the vicinity of wind farms. For example, around 30kms out to sea from Orford Ness lies the Galloper Offshore Wind Farm although the site isn’t mentioned specifically in the report.
Furthermore, scientists also found birds to be at risk once the breeding season is over and they disperse south to Spain, Portugal and north Africa, where they overwinter.
As the number of offshore wind turbines increases, not just off the East Anglian coast but worldwide, scientists have been working to assess their potential threat to bird life using the same airspace in the hope that the information can help support decisions about where best to locate wind farms. While the BTO has conducted a number of similar studies, this is the first to look at the entire yearly life cycle of bird species.
Dr Chris Thaxter is a senior research ecologist at the BTO, and lead author of the paper, which appeared in the Journal of Applied Ecology earlier this month. He said: “We knew that lesser black-backed gulls were at risk of colliding with wind turbines, but what we didn’t know was where and when birds from specific breeding colonies may be most vulnerable across their annual life cycle.
“The fact that we have been able to answer some of these questions is testimony to the advances in tracking technology we have seen in recent years. Mapping vulnerability to collision risk in this way can also help identify where may be best to site new wind farms in the future to minimise any harm to wildlife.”
The UK is a global stronghold for breeding lesser black-backed gulls and although the species can be unpopular with people during the summer months due to individual tendencies to steal chips and nest on rooftops, it is Amber-listed in the UK’s Birds of Conservation Concern and is protected by law.
Co-author on the paper Dr Viola Ross-Smith, added: “We were surprised to see how vulnerable lesser black-backed gulls could be to collision at some of their wintering destinations, such as Lisbon and Malaga, as well as when they were on migration. Galicia in northern Spain stood out as a spot where birds were vulnerable. This region contains a high density of wind turbines and is an important stopping over site for lesser black-backed gulls, as well as for many other migratory bird species.”
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