Sea Mammals

Seals

The only seal to frequent the shores of St Kilda is the Atlantic grey seal. The inhabitants once hunted the seals, their dried skins contributing towards rent. Once the human population abandoned Hirta seals moved in to breed. Pups are born in October and November. Before the MoD Base was constructed some pups were born on the beach below the Manse. A few were dropped at Mol Ghiasgar and at Mol Shoay but most are to be found on the flat, sloping rocks of Dun where there were about 30 or so pups born in 1957 and 100 the following year. There are fewer now with increased disturbance by the visitors and traffic to the Base. Around 300 to 400 adults and juveniles frequent St Kilda’s shores throughout the year with the main concentrations in Glen Bay, Soay Sound and on both sides of the neck of the Cambir. Their calls echo round the Tunnel at Gob na h-Airde and, appropriately enough, at Geo nan Ron – the cleft of the seals.

Cetaceans

Sightings of cetaceans have increased in recent years, probably because of more interest, better data collection and more observers experienced in identification. To date 37% of records of cetaceans were inside or crossing the mouth of Village Bay; 23% of records were from elsewhere on the Hirta coast and 9% were from Boreray; 23% of the reported sightings were from vessels at sea. Most are made in the summer months May to August but some killer whales, harbour porpoises and Risso’s dolphins have been seen in the period November to March. Ten species have been sighted from St Kilda so far, all but one known to occur regularly off the Scottish west coast in summer. The exception was a Sowerby’s beaked whale that was washed up in Village Bay on 29 September 1994.

Sowerby's beaked whaleMinke whale is the most commonly recorded species of cetacean, usually occurring in ones or twos, but occasionally in greater numbers with as many as five and eight being seen in one day, and exceptionally on 2 August 1984 no fewer than 15 were seen from Hirta. Killer whales are the next most commonly seen species, typically no more than two reports a year, usually between May to August. There have also been a few sightings in February, March and October. Pods vary in size, with an estimated 40 to 50 animals being seen in July 1984. Occasional groups may remain around the islands for several days or even weeks. Some have been seen breaching in Village Bay and in February/March 1996 they were seen lob-tailing close inshore, and playing with a freshly-killed grey seal.

Groups of up to 15 Risso’s dolphins have been seen, as well as white-sided dolphins; on one occasion 200 of the latter speces were observed off Village Bay on 2 July 1984 and 50-60 actually inside Village Bay on 29 July 1996. Harbour porpoises were first recorded in 1988 but usually only single individuals. Small numbers of white-beaked dolphins have been seen with a maximum of 20 in Village Bay on 21 July 1990. These animals are probably more common further offshore, Bottlenose and common dolphins are rarely observed but large whales are occasionally recorded.