The Deer Park at Martin’s Haven, near Marloes, which overlooks the point of embarkation for pleasure boats taking visitors out to Skomer Island or round Grassholm, is a favourite grandstand for bird and seal watching.
Separated from the mainland by a deep ravine, It is almost an island, and its name is somewhat misleading since it is not recorded that any deer ever populated it and the terrain does not seem capable of sustaining any.
It was intended as a embellishment of the nearby Edwardes estate, from which family the wealthy Kensington dynasty stemmed, and who built St Brides Castle. The Edwardes also had a large mansion at Sealyham where one of the family bred the famous Sealyham Terrier, designed specifically for hunting badgers. The Kensingtons also owned large and valuable estates in London, notably Kensington, where Pembrokeshire names like Edwardes Square and Marloes Road reflect places in their Welsh estate.
The Deer Park has a flourishing seal colony and many visitors use the viewing point on the high western cliffs to watch seals and their pups on the inaccessible pebbly beaches in the rocky coves below, Seals are there all year round, and usual oblige observers by popping their sleek heads above water to watch the watchers watching them. October is the best time not only to see them suckling their young but to hear their mournful songs, seemingly in close harmony, wafting up from beneath the cliffs on a cold and windy autumn day. About 50 Atlantic grey seal pups are born each year on the beaches around the peninsula, making the cliffs above the beaches on the deer park excellent for cliff-top seal watching. Seal pups can be spotted on the small beaches at the west end of the deer park in late summer and Jack Sound is a popular haunt for porpoises.
Choughs nest and feed on the cliffs, which are also the breeding site for gliding fulmars. People unversed in things ornithological can miss seeing the choughs, for they closely resemble their cousins the jackdaws at a distance, except that their calls are more asthmatic and their flight more erratic. At close quarters there can be no mistaking them, for the chough has a vivid red downward-curving beak and orange legs. From the cifftop at Wooltack Point or Anvil Head views of the bird-sanctuary islands Skokholm and Skomer are visible and, on clear days, distant Grassholm and the candy-striped lighthouse on The Smalls rock.Razorbill is just one example of the many seabirds you can spot on the peninsula. Guillemots, puffins and razorbills breed in huge colonies on Skomer and Grassholm is one of the largest gannetries in the world. Wooltack Point is a good vantage point for watching seabirds fishing during the spring and summer. This area is also a very popular breeding ground for the distinctive chough (with its red legs and beak), which can be seen all year round.
Look out for Welsh mountain ponies on the deer park. Their grazing is essential for keeping the coastal heathland vegetation in good order. Heathland plants, such as heather and gorse, need nutrient-poor acidic soils to grow, however, modern farming practices have increased soil fertility by applying lime, manure and fertiliser. Trehill Farm is part of an important experiment to provide more favourable soil for heathland by stripping topsoil and speeding up re-acidification by adding sulphur, a by-product of the oil refinery at Pembroke.