An island off the coast of south-east Alaska.
It's called St Lazaria, after a saint of the Russian Orthodox Church. Alaska was once Russian.
It's quite small, only 1,000 metres from end to end. Its rocky shores make it difficult to land on.
No people live here, but in summer it's home to more than half-a-million birds.
Spring comes late to Alaska,
and it's May before tufted puffins come ashore to lay their eggs.
Some 11,000 of these punk-plumed puffins breed on St Lazaria.
Like our own Atlantic puffin,
these Pacific puffins nest in burrows, on the grassy slopes above the cliffs.
In Britain, puffins sometimes use rabbit holes. There are no rabbits here so they dig their own burrows.
The same holes are used year after year.
One of the first tasks of the newly arrived pairs is to collect material for the simple nest.
Despite all the energy that goes into gathering these leaves, hardly any will be taken into the burrow.
Perhaps collecting grass is a vestige of the time when puffins made proper nests,
or perhaps grass and twigs are a suitable gift
to impress a mate, the puffin equivalent of a bunch of flowers.
Tufted puffins are by no means the only kind of sea-bird to come to the island.
It's a varied place and there's ground to suit many tastes.
Glaucous-winged gulls nest on the grass crests of cliffs and pinnacles.
Kittiwakes, fishing in the sea near the island, rest on its cliffs.
Tidal pools in the low centre of the island yield food for other birds.
Sandpipers.
And black oyster-catchers probing for a meal.
Crevices in the rocks provide nest sites for pigeon guillemots.
And on the steep cliffs facing the gulf of Alaska,
common and thick-billed guillemots line the ledges.
Exposed to the full force of storms surging in from the Pacific,
they perch precariously, cradling their single eggs between their feet.
Ten kinds of sea-bird breed on St Lazaria.
That makes it a magnet for scavengers and predators.
The bald eagle, the national bird of America.
Alaska is one of the few areas that still support good numbers.
Most years, one or two pairs of these powerful birds nest on the island,
supplementing their diet of fish by plundering sea-bird colonies,
and even snatching puffins from the surface of the sea.
An Indian legend maintains that St Lazaria was born in fire,
cast from the throat of a volcano just across the sea.
Geologists agree that these rocks are volcanic,
the result of an upwelling of lava some 40,000 years ago.
The lava cooled and the sea sought out lines of weakness in the rock,
carving it into strange arches and pinnacles.
Caverns run deep into the cliffs.
Where their mouths open below high-water mark,
they form blow-holes.
Waves, surging in, compress the air trapped within the cave...
.. until the pressure builds and it blasts its way out.
Even in midsummer huge waves beat upon St Lazaria's exposed shore.
They may have travelled hundreds of kilometres from some distant storm-centre in the Pacific.
Often they sweep across the outer barriers of rock, flooding the low centre of the island.
But the water in one pool rises mysteriously with the tide, even on a calm day,
even though a rock barrier completely separates it from the sea outside.
Sometimes a seal appears from the limpid depths of the pool, as if from nowhere.
There is clearly a hidden link with the sea, a channel through which water, and the seal, can enter.
In the centre of the pool, a narrow shaft leads straight down,
perhaps following the line of some ancient outpouring of molten rock.
Fifteen fathoms down, it turns and becomes a horizontal gallery.
Incredibly, in what is normally total darkness,
the walls of this submarine passage are encrusted with brilliantly coloured corals.
The fissure leads on into the darkness,
not straight to the sea, but towards the centre of the island.
It's never been followed to the other end, but it must ultimately run to the open sea.
Wolf eels and tiger rock-fish usually live on the deep reefs around St Lazaria.
It may be the search for such fish that draws seals into this submarine tunnel.
On the cliffs above the pool, the puffins are well-established.
By June, most burrows will have a single egg.
While one partner incubates, the other is free to fly out to sea to feed.
Some days the colony seems almost deserted;
on others, there's a constant coming and going.
This tapping of bills is part of puffin courtship.
All the breeding birds in the colony will have found a mate weeks before,
but they still bill-tap with their partners.
This continuing courtship seems to strengthen the bonds between them.
Bill-tapping pairs often attract onlookers.
Although the burrows are packed close together, puffins are territorial.
Each pair defends a small area around the hole.
This yawning is a kind of threat, warning off an intruder.
If intimidation fails, they may come to blows.
Tufted puffins account for only a tiny proportion of St Lazaria's breeding birds.
Most of the others are found, not on the cliffs or grassy headlands,
but in the small patches of forest that crown the ends of the island.
The trees are Sitka spruce.
Some may have survived the storms of three centuries.
They're watered by two-and-a-half metres of rain a year,
that's enough to cover a tall man.
Like the jungle of the Amazon, this is a rain forest,
not a tropical, but a temperate one.
During the day, the forest seems almost deserted.
Most of its inhabitants are hidden or absent.
Only in the brief Arctic night does it come alive.
In a honeycomb of burrows beneath the trees, something is stirring.
BIRD CALLS
From far out to sea, there comes a winged invasion.
Storm petrels.
They're called petrels after St Peter who, the Bible says, once tried to walk on water,
as petrels often flutter and patter with their feet as they feed on the surface of the sea.
These frail birds may fly hundreds of kilometres to reach the island.
They must time their arrival for the short hours of darkness, for only then are they safe.
An estimated 540,000 petrels nest on St Lazaria.
They congregate here
because very few islands are free of ground-based predators, such as rats or mink,
and have soil that is soft enough to burrow into.
They dig tunnels the length of a man's arm. Like puffins, they use their nest-holes year after year.
Two kinds of petrel nest on the island.
This is the forktail petrel.
The other one's called Leach's petrel. They're about the size of a blackbird.
Petrels have a prominent nostril on the upper part of their beak.
They're unusual among birds in having an acute sense of smell.
This may help them find food on the surface of the ocean,
and petrels locate their own burrows at least partly by smell,
though if their mate is at home, the partner may identify it by its calls.
BIRD CALLS
Petrels lay only one egg.
A forktail's egg takes seven weeks to hatch, longer than almost any other bird's.
Petrels feed far out to sea and the egg is often abandoned for days at a time.
There's only the scantiest nest to raise it off the damp ground.
It'll survive a drop in temperature that would kill most eggs.
An egg has been known to hatch after 71 days, for 31 of which it was unattended.
With the parents away so much, the chick may hatch alone.
A chick can survive being chilled but its chances are greater if it's brooded for the first few days.
It can't generate its own internal warmth until it's four days old.
Petrels aren't the only burrow-nesting birds in the forest.
This is a rhinoceros auklet, so-called from the strange growth on its bill.
It's a kind of secretive, nocturnal puffin.
About 2,000 of these birds nest on the island.
During the day, they remain offshore.
Only at night, do they bring fish for their young, which are waiting hungrily in the burrows.
Petrels don't feed their chicks on fish.
They eat tiny shrimps and squid,
caught far from the island, beyond the contintental shelf.
Instead of bringing them back whole they store the natural oils derived from their prey in their stomachs,
and regurgitate it when they return to the nest.
Visits to the open ocean take parents away for two to three days at a stretch,
so it's not often that both are in the nest-hole together.
This pair may not have seen one another for many days.
Their chick hatched only hours ago.
The returning parent hasn't yet seen what's become of the egg
which it's been helping to incubate for the last seven weeks.
It will be some sixty days before the chick leaves the nest.
For much of that time, it will be left on its own.
This chick was abandoned within two days of hatching.
It's able to conserve its energy by greatly slowing down its heartbeat and respiration,
but these early days are nonetheless critical.
Four days later, one parent returns to deliver its cargo of oil.
While its parents were away, the chick has managed to grow,
using the remnant of the yolk still within its body.
Now with this feed of energy-rich oil, its chances of survival are good.
Petrels that don't remain in the burrows must be clear of the island before dawn.
Their sole defence is to spit sticky, foul-smelling oil over an attacker
and that would hardly deter a stooping eagle or peregrine.
A feeding frenzy of gulls greets the sunrise.
Beneath them swim vast shoals of sand-lance.
For the sea-birds, these teeming finger-length fish
are one of the great riches of the Gulf of Alaska.
They're eaten by almost every kind of bird.
Only in the submarine forests of kelp are they relatively secure.
This bull kelp is an annual plant.
In the spring, its stalks grow several metres in a few weeks.
At the top of each, a gas-filled bladder develops
which holds up the frond near the surface in the sunlight.
On the sea-floor, far below, the kelp has an enemy.
Sea-urchins graze on the stems that anchor the kelp to the sea-bed.
They sever the stalks. The rest of the plant drifts away, perhaps to sink and be eaten by other urchins.
The sea-urchins have an enemy too,
the sea-otter.
A few years ago, there were no sea-otters here.
They were wiped out in the last century by Russian fur traders based in nearby Sitka,
or "New Archangel", as this capital of Russian America was called.
But recently sea-otters were re-introduced and their numbers are now increasing.
More sea-otters mean fewer sea-urchins.
Fewer sea-urchins means more kelp.
More kelp may mean more little fishes for the puffins to eat.
It's August and the tufted puffin chicks have hatched.
A constant stream of parent birds bring beakloads of sand-lance for their young.
Puffins can dive down to sixty metres below the surface in pursuit of fish.
They don't deliver the fish right to the chicks' beaks.
They just dump them in the burrow or sometimes even at the entrance,
and leave the chick to pick them up for itself.
Each load may be several small fishes and squid, all neatly aligned in the beak.
So how do puffins collect this mouthful?
It's thought the puffin holds the first fish it catches
against the upper part of its beak with its tongue, and then uses the lower mandible to catch more.
For the time being, the puffin chick is well-fed.
But in a few weeks its parents will desert it and it will make its first journey out to sea alone.
By November the puffins and petrels will have left and the island will will be deserted, except for seals,
until once again, in spring, it will provide a home for half-a-million birds.
Subtitles by Dorothy Moore BBC Scotland 1988