0:00:10 > 0:00:14This is no ordinary story about a beautiful and faraway island
0:00:14 > 0:00:18tucked away in a remote part
0:00:22 > 0:00:25by the wild Atlantic Ocean.
0:00:38 > 0:00:40There are some creatures here,
0:00:40 > 0:00:44that you probably wouldn't expect to find on a far-flung rocky shore.
0:00:46 > 0:00:49and no ordinary sheep at that.
0:00:49 > 0:00:52They are one of the wildest
0:00:52 > 0:00:55and have lived on the island
0:00:58 > 0:01:04They were old before the first
0:01:09 > 0:01:12but that's not what makes them
0:01:16 > 0:01:25they were thrown out of their fields
0:01:41 > 0:01:45North Ronaldsay is the most northerly of the Orkney Islands
0:02:03 > 0:02:07are an unspoiled grassy paradise.
0:02:09 > 0:02:11with plenty of time to rest
0:02:15 > 0:02:19when everything will change.
0:02:21 > 0:02:23They are in for a big shock.
0:02:23 > 0:02:27Although it might all look lovely for these little lambs now,
0:02:27 > 0:02:31they are no ordinary breed,
0:02:38 > 0:02:40is a rather curious old wall
0:02:40 > 0:02:43which more or less completely encircles the whole island.
0:02:48 > 0:02:51the sheep out rather than in.
0:02:51 > 0:02:56stay in the green fields for long.
0:03:00 > 0:03:03Soon they too will be banished
0:03:07 > 0:03:10of their kind in the world.
0:03:18 > 0:03:22Instead of starving, they've taken
0:03:57 > 0:04:01of the little lambs' destiny.
0:04:03 > 0:04:06The newborn lambs and their mothers
0:04:06 > 0:04:09are allowed to spend spring
0:04:09 > 0:04:11The grass helps the nursing mothers
0:04:14 > 0:04:20A charmed existence with beautiful,
0:04:22 > 0:04:27from thousands of miles away.
0:04:27 > 0:04:31By the time the terns migrate south
0:04:31 > 0:04:33the lambs' lives will change
0:04:42 > 0:04:46Starlings are rearing families
0:04:54 > 0:05:00they don't seem very interested
0:05:26 > 0:05:29their flying skills round the wall,
0:05:31 > 0:05:34practice flights turn into races.
0:05:52 > 0:05:55They are rounded up from the beach
0:05:55 > 0:05:58to be counted and checked out.
0:05:58 > 0:06:01Although they live pretty much
0:06:07 > 0:06:08By now, you might be wondering
0:06:08 > 0:06:12why the sheep are kept shut out
0:06:12 > 0:06:17Why was a wall built which forces them to live out on the beach?
0:06:19 > 0:06:22the laird of the island decided
0:06:22 > 0:06:26to be made from rearing cattle
0:06:34 > 0:06:37while the little native sheep were banished to the beach.
0:06:39 > 0:06:44who'd survived for millennia.
0:06:44 > 0:06:48They became one of only a handful of animals in the whole world
0:06:54 > 0:06:57so the sheep evolved and have become very efficient at extracting it.
0:07:03 > 0:07:08of banishment, their unusual diet
0:07:08 > 0:07:10has fundamentally reshaped the way
0:07:14 > 0:07:17They can now die if given grass
0:07:25 > 0:07:30must make them very thirsty.
0:07:30 > 0:07:34Luckily, there are a few springs
0:07:34 > 0:07:38close enough to the island's shore to keep the sheep in drinking water.
0:07:44 > 0:07:45Instead of grazing in the day
0:07:45 > 0:07:50and chewing the cud at night
0:07:50 > 0:07:58the island breed have adapted to the rhythm of the tides.
0:08:03 > 0:08:36They are an amazing example
0:08:52 > 0:08:55E-mail subtitling@bbc.co.uk