Normally it is a terrible idea to steal eggs from the nests of wild birds. That is doubly true if the species is endangered, in which case every individual counts. In the UK, anyone caught with a wild bird’s egg can be sent to prison for six months.

But in the chilly coastal tundra of Chukotka, in the remote north-east of Russia, conservationists are doing exactly that. Beginning in 2012, Russian and British ornithologists have been taking the eggs from the nests of spoon-billed sandpipers. These little wading birds are critically endangered.

This is no sport, however, and it is entirely legal. The conservationists are raising the stolen chicks themselves, because that way the young birds have a far better chance of survival. Once they are large enough to survive on their own, they are released into the wild.

It is a desperate, last-ditch approach to conservation. But those involved are doing it because the spoon-billed sandpiper’s situation is equally desperate.

There are only about 200 breeding pairs of spoon-billed sandpipers left in the wild. The population has declined rapidly over the last few decades.

This is a migratory journey of some 4,970 miles, undertaken by a bird no larger than a sparrow

The source of this crisis does not lie in their breeding habitats in Russia, but far to the south.

Once a young spoon-billed sandpiper has reached the right size, it embarks on an epic migration. It will head south to the Chinese and South Korean shores of the Yellow Sea, and then on to South East Asia.

This is a migratory journey of some 4,970 miles (8,000km), undertaken by a bird no larger than a sparrow. And it is on this journey that the sandpipers face their greatest challenges.

The birds’ habitats in the Yellow Sea have been almost swept away.

Away from the Russian tundra, spoon-billed sandpipers are shorebirds. They feed on intertidal mudflats, which are home to millions of small invertebrates.

Most of their eggs and chicks fall victim to predators

But in China and South Korea, these once vast muddy beaches have been converted to dry land for agriculture and industry. That means there are fewer places for the birds to refuel on their gruelling migration.

The habitat loss in the Yellow Sea is a crisis for many migratory shorebirds. These birds all travel along the East Asian Australasian Flyway, which stretches halfway around the world and is one of the great bird migratory routes. Bar-tailed godwits and eastern curlews are also in population free-fall.

Shorebird hunting is also a problem, particularly in South East Asia and south China. Spoon-billed sandpipers are too small to be worthwhile targets for hunters, but they are caught as bycatch in the mist nets set for larger species.

To offset these losses, the sandpipers need to produce lots of young. But that is also something they struggle with.

Spoon-billed sandpiper parents have the odds stacked against them.

Most of their eggs and chicks fall victim to predators, in the form of larger birds, like skuas and gulls, and mammals like foxes and ground squirrels. On average, a breeding pair will produce three or four eggs each year, but they will only add one youngster every two years to the population flying south.

This is where the conservationists come in.

They steal eggs and keep them in incubators. Then they care for the newly-hatched chicks, until the young birds are large enough to fend for themselves.

The process is known as “head-starting”. The idea is to harvest eggs as soon as they are laid, then raise the hatchlings in the safety of a temporary aviary.

In theory, head-starting means about seven times more youngsters get the opportunity to start the migration to the Yellow Sea.

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