Intensive husbandry ceased in 1974 with the Islanders' departure. No hay has been given in winter since 1977. In October 1977, a number of cattle (estimated as 13 or 14) were removed for sale.(ref. S.J.G. Hall and G.F. Moore - Feral cattle of Swona, Orkney Islands, Mammal Review 1986)
The herd originated from a cross between Aberdeen Angus and Shorthorn stock. They now form one of the very few feral herds of Bos taurus in the world, which is of considerable interest to scientists. The cattle mostly graze on the richer grass near the houses, however they do also forage for seaweed, but not in the inter-tidal zone. The cows survive longer than the bulls and calving is in Spring, as with other Orkney cattle. The Swona cattle tend to stay together as a group rather than foraging individually, and there seems to be no system of territories for the bulls.(ref. The Orkney Guide 2005, C. Tait)
Numbers settled into the high teens during the 90s (no data displayed) and began to recover from 2006 to 2016. At which point a healthy herd number of 26 was recorded. Recent years have seen a sharp decline due to accidental stampede caused by search and rescue helicopter activity and the harsh winter of 2017/18.
Below shows the reported number of Swona Cattle over time.
These records show the last two bulls brought to the island; a Shorthorn Bull in 1962 (green sale document) and an Aberdeen Angus bull in 1963 (red sale document).