After flying thousands of kilometres from faraway Bangladesh and New Zealand via the Yellow Sea, the shorebirds of the East Asian Flyway complete their northward migration. They touch down in the Arctic Russia and Alaska to breed.

In May and June, birds such as the endangered spoon-billed sandpiper and red knot fill the air of the Russian tundras with their mating calls and display flights. But why travel so far to raise the next generation?

Presenter Ann Jones also discovers why Russian and British conservationists are taking eggs from the nests of the spoon-billed sandpiper, the most endangered shorebirds in the world, in a last ditch effort to save the species from extinction.

Finally, with the mating season finished and a new generation ready to migrate for the first time, we follow the incredible non-stop flight of nine days by the bar-tailed godwit, as it migrates south from Alaska all the way to New Zealand. The record-breaking species is helped by somehow being able to sense the weather patterns across the entire Pacific Ocean.

The series is a co-production from the BBC World Service and Australian ABC Radio National. The sound recordings from Russia and Alaska were provided by the Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology.

(Photo: Spoon-billed sandpiper chick in Chukotka, NE Russia. Credit: Nicky Hiscock)