The direct cause for the breeding failure of common guillemots, Arctic skuas, great skuas, kittiwakes, Arctic terns and other seabirds at Shetland and Orkney colonies was a shortage of small fish called sandeels, a crucial prey species for the seabirds.
As a result, the nearly 7,000 pairs of great skuas in the Shetlands, for example, produced only a handful of chicks and starving adult birds ate their own young.
Warming ocean waters and major shifts in species that underpin the ocean food web are thought to be behind the major sandeel decline.
