Antarctica is still locked in ice,
and surrounded by a frozen ocean.
Nonetheless, there are signs of spring.
Adelie penguins are arriving. Just the males.
They've spent five months at sea,
where it's warmer than it is on land,
and now they're in a hurry,
for spring will be short.
They have travelled 6,000 miles across the ocean
since leaving their colony last year
and now, they're returning to breed.
They cannot lay their eggs on ice for they would freeze.
So they have to come here,
where there is bare rock.
Over the coming months,
the few parts of Antarctica that are ice-free
will be the stage on which five million Adelies
will build their nests.
To construct one, they need pebbles.
And without a good-looking nest,
a male will be unable to attract a female,
when they at last arrive.
An impressive property demonstrates your worth as a mate.
It takes stones of all shapes and sizes to build a decent nest
and finding ones that are just right is not easy.
So, some penguins turn to a life of crime.