'There were a few porpoises here just days ago but a pod of seven or eight killer whales chased them away,” said Tom Jamieson, the ferryman. “However, you never know what might appear.”

Hearing this, a number of passengers aboard the Solan 1V readied their cameras and binoculars as the boat eased away from the pier and headed into the Sound of Mousa.

The ferry crossing to the Island of Mousa, an RSPB Nature Reserve off the east coast of the south mainland of Shetland, takes about 15 minutes from the township of Leebitton.

From Mousa pier, a roughly circular trail around an area in the middle of the island has been marked out with short posts. Using these as a guide and a brochure map we began an easy walk on springy turf.

It’s no distance across the narrow neck of land to the opposite rocky shore of an inlet that reaches far in from Mousa’s east coast. Here our first sighting of the abundant bird life was a chorus-line of shiny black shags (scarfs in Shetland dialect). Seemingly unperturbed, they stood on sun warmed rocks, wings spread akimbo, catching a drying breeze.

The path follows the shoreline of the inlet then turns southwards to wind through long grass covering the hillside. The

downward slope ends in a craggy coastline battered constantly by the North Sea.

Further along, the path reaches a flatter area of shore that is protected by a dry stane dyke. Peer over this wall to the inlet known as the East Pool and there’s a very good chance of spotting Grey seals and Harbour seals. Grey seals are more horse-like in profile with a flatter head and longer snout. Harbour seals have a shorter muzzle.

The nearby West pool is a much larger lagoon with a more open aspect. On the day our party were exploring Mousa, the West Pool had an impressive number of seals (selkies) visible in the water while more were hauled up on the surrounding sand.  When a few of the beached seals did shuffle awkwardly back into the sea, they only retreated to the comparative safety of the pool yet were still within good viewing distance.

With so much wildlife present, this is obviously a sensitive area and the ground-nesting artic terns (tirricks) and great skuas (bonxies) soon let you know that you are getting too near their territory. In at least one instance, blood was drawn as a member of our party strayed too close and was pecked on the head for his trouble.

It’s strange to see people walking with their arms in the air, shaking their hands and fingers all the while, but this is the advised method of protection against these aerial attacks. It’s best, of course, if you can leave the wildlife in peace, undisturbed.

From the beach, the trail now leads back up the hill. Big, brown, great skuas still make their presence felt here, swooping low, squeaking then soaring skywards.

Dainty, white flags of bog cotton grow in the wettest areas while broken walls and the stones of an old water mill are smothered in tufts of silver grey algae known in Shetland as Old Man’s Beard. This growth is said to signal the absence of pollution and the purity of the air.

When the way ahead flattens out, Mousa Broch dominates the view. This is the best preserved broch in the world (there are none outside Scotland). Built around 2000 years ago of local sandstone, it still stands over 13 metres high. Possibly, there was at least 1 metre more of stone, now long gone, on the top of the building which was probably roofed with timber and turf, or thatch.

Brochs are thought to have been symbols of power as well as fortified farmhouses for the leading families of the area. Safe inside, the inhabitants could hold out against attacks by enemies who might be using the best weapon technology of the day.

There may have been three wooden floors inside giving living spaces that could be reached from a stone stairway winding clock wise between the inner and outer walls. It’s thought that symbolically and perhaps spiritually, there was some significance in this clockwise design of stair construction.

When you follow in the footsteps of the Iron Age broch dwellers and climb up the stairs, the views from the top are vast. From up here, the siting of Mousa Broch and another broch that once stood on a headland across Mousa Sound at Burraland would suggest these structures were also used as watchtowers.

  The Broch has given refuge to at least two famous runaway couples. In 900 AD, a couple from Norway were on their way to Iceland when they were shipwrecked on Mousa. They married and spent a winter in the broch.

In the 12^th century, Harald, Earl of Orkney laid siege to the broch where his mother and her lover were taking refuge, but eventually matters were settled amicably and they left the island.

In 1774, eleven families lived on the isle, but by 1861 all were gone.

From the Broch, the marked trail leads back to the ferry pier. It’s worth walking on a little way to see a part of the coastal geology where the rock appears to have been formed like a sandwich cake, from layers of a near-similar thickness. Slices of this sandstone were used to make flagstones for the streets of Lerwick, the capital of Shetland.

Having taken our seats aboard the Solan 1V for the return journey and now moving at a good rate of knots across the Sound of Mousa, we were surprised when the ferryman cut the engine. In the ensuing silence, 3 or 4 porpoises could be seen, dorsal fins arcing out of the water only a few metres from the boat - an added bonus to a splendid day.

Back on the pier at Sandsayre it’s worth taking time to explore the old boathouse which has been converted into a small waiting room/ heritage centre with wall panels giving information on the history and natural history of the area.

Further Information: The smallest British seabird, the storm petrel (aalamootie) breeds on Mousa and there are special evening trips to the island to watch these tiny birds returning to their breeding sites. Bat-like, they flutter in from the sea, disappearing into crevices in the walls of the Broch with cropfuls of food for their single chicks.

              Daily trips between early April and September

              Tel: 01950 431367

               First published in Scottish Islands Explorer Magazine  May/ June 2012