0:00:03 > 0:00:07Through the brooding sky and over the furious sea they come.
0:00:16 > 0:00:21Just when the great winter storms crash against the shore, they arrive.
0:00:27 > 0:00:30Silhouettes amongst the clouds,
0:00:30 > 0:00:31like angels.
0:00:34 > 0:00:38First, a few, struggling against the North Wind.
0:00:38 > 0:00:42Then, more and more, skein after skein,
0:00:42 > 0:00:46until the sky is full of thousands of them.
0:01:04 > 0:01:08The storm geese come to the Scottish island of Islay,
0:01:08 > 0:01:10one of the Hebrides,
0:01:10 > 0:01:14the chain of islands which lie along Scotland's western coast.
0:01:16 > 0:01:21It's a wild and rugged place, with great natural beauty.
0:01:22 > 0:01:24And, until the autumn,
0:01:24 > 0:01:29there's no sign that it will host a spectacular invasion
0:01:29 > 0:01:31of thousands of geese.
0:01:40 > 0:01:43It's mainly barnacle geese that come,
0:01:43 > 0:01:48valiant birds who migrate here on an epic journey of 2,000 miles
0:01:48 > 0:01:51over the wild North Atlantic.
0:01:51 > 0:01:53They'll stay until spring,
0:01:53 > 0:01:56when warm weather signals it's time
0:01:56 > 0:02:01to return to their distant summer nesting grounds.
0:02:01 > 0:02:04Until the 19th century, no-one knew where they went.
0:02:04 > 0:02:06It was a mystery.
0:02:06 > 0:02:10Then, they were discovered breeding in Greenland,
0:02:10 > 0:02:16where they feast on grass in Arctic meadows during brief northern summer.
0:02:16 > 0:02:19The big winter freeze would mean starvation.
0:02:19 > 0:02:23So, when autumn comes, they all have to fly south...
0:02:23 > 0:02:25no matter what.
0:02:32 > 0:02:38As the wild storms lash against Islay's shores, at the dark end of the year, they come.
0:03:20 > 0:03:23More than 40,000 of them,
0:03:23 > 0:03:2770% of Greenland's entire population.
0:03:29 > 0:03:36Why should so many birds choose one particular island as their winter home?
0:04:01 > 0:04:03Islay is a special place,
0:04:03 > 0:04:07world famous for its whisky.
0:04:07 > 0:04:11But not quite so well known for its rather unexpected climate.
0:04:14 > 0:04:18The island is the most southern of the Scottish Hebrides
0:04:18 > 0:04:24and although its Atlantic location means it is lashed by winter storms,
0:04:24 > 0:04:28it also gets bathed by the warming waters of the Gulf Stream.
0:04:30 > 0:04:35Islay enjoys more sunshine than most of mainland Britain.
0:04:35 > 0:04:37And even in winter,
0:04:37 > 0:04:39frosts and snow are rare.
0:04:39 > 0:04:44But it's not just the balmy temperatures that pull in the crowds.
0:04:48 > 0:04:54Even in the depths of winter, parts of Islay have an emerald glow.
0:04:54 > 0:04:59The beautiful colour of the living, growing grass.
0:05:02 > 0:05:07The gentle climate means that it can pretty much grow all year round
0:05:07 > 0:05:11and lots of grass means lots of food for grazers.
0:05:15 > 0:05:19Islay has even more attractions for feathered Arctic visitors.
0:05:19 > 0:05:23Not only does it provide very good food,
0:05:23 > 0:05:26it also boasts luxury accommodation.
0:05:28 > 0:05:30Two large and shallow sea lochs -
0:05:30 > 0:05:35the barnacle goose equivalent of five-star hotels.
0:05:38 > 0:05:43Safe and muddy dormitories where the flocks can relax and roost safely.
0:05:47 > 0:05:50Geese don't mind wet feet on wintry nights,
0:05:50 > 0:05:54whereas predators, like foxes, do.
0:06:05 > 0:06:07Away from the fields and mudflats,
0:06:07 > 0:06:11life isn't quite so easy for other wildlife.
0:06:11 > 0:06:15Red deer stags are trying to fatten up after the rut.
0:06:15 > 0:06:18Though their mating season is over,
0:06:18 > 0:06:21some hotheads still forgo feeding to lock horns with each other.
0:06:35 > 0:06:39But, for the wild geese, the struggles are over.
0:06:39 > 0:06:43They have found a safe sanctuary...
0:06:43 > 0:06:47along with other birds, like families of mute swans.
0:07:09 > 0:07:11And flocks of whooper swans too.
0:07:32 > 0:07:37The miracle of the geese is not just their epic migration,
0:07:37 > 0:07:41it's the fact that there are now probably
0:07:41 > 0:07:45more barnacle geese alive today than ever before.
0:07:45 > 0:07:47They are protected
0:07:47 > 0:07:51and have learned to graze our crops and fields.
0:07:51 > 0:07:53That doesn't always make them popular.
0:07:53 > 0:07:58But on Islay, everyone is aware of how important their island is
0:07:58 > 0:08:02for these creatures, and for the transformation that they bring.
0:08:07 > 0:08:11Last year, 18,000 arrived on the same day.
0:08:18 > 0:08:20So how do you know when they'll come?
0:08:22 > 0:08:26At the end of autumn, when the North Wind blows,
0:08:26 > 0:08:28look out at the stormy sea...
0:08:28 > 0:08:32and wait for angels.
0:08:52 > 0:08:55Subtitles by Roger Young Red Bee Media Ltd - 2005
0:08:55 > 0:08:58E-mail subtitling@bbc.co.uk