France, Oct. 25 -- Ruth Kruse's family has lived on the island of Nordstrandischmoor in northern Germany for more than 300 years. And for as long as anyone there can remember, the comings and goings of migratory and breeding birds have set the rhythm of their daily lives.

The bird that symbolises the Halligen is the oyster catcher - 4 percent of the global population of the species nests on these islands.

"Here, on our Halligen islands, more than 10,000 black-headed gulls nest," Kruse told RFI. "I also counted 400 pairs of common terns, as well as little terns, common ringed plovers and, of course, the oyster catcher, which is listed on the Red List of threatened species."

She added: "Some colonies number up to 2,000 breeding pairs, or...