The Soay sheep are an ancient breed, and probably resemble the first breeds domesticated in Northern Europe in the Bronze Age. They have been on the St Kilda archipelago for a period of several thousand years, for most of which time they lived on the island of Soay, separate from the human population (who themselves have a fascinating history) on the island of Hirta. When the human population left Hirta in 1930, 107 sheep were moved from Soay to Hirta, and the expanding population has been studied intensively since 1985.
Individuals in the Village Bay area of Hirta (above) are tagged at birth, genotyped and blood sampled within a week at birth: a lot of running around is required to catch them!
In August, a large team attempts to catch as many sheep as possible in the population; usually around 50% are caught through deploying a range of cunning netted and walled traps (below). When captured, sheep are weighed, measured, blood sampled and released as quickly as possible (below).
During the rut in autumn, males are observed in consort with females and unknown males are darted and tagged. The Soay sheep are highly promiscuous compete with each other (below) to mate with as many females as possible to achieve the highest siring success.
This effort means that the Soays are one of the best-studied wild populations in the world. For more information, see the St Kilda Soay sheep project website.