Wetenschap - 13 september 2001

Tracking birds in the barren tundra

Tracking birds in the barren tundra

Alterra biologists search for new information on protected birds

Three months in the barren tundra, keeping track of the grey plovers and other wading birds: for Hans Schekkerman and Ingrid Tulp it was a fascinating time in Siberia, with the hope that new insights might help save these precious birds.

Every year they fly thousands of kilometres from Siberia to western and southern Europe and Africa, and back again: the brent goose, curlew sandpiper, dunlin and many other birds that prefer coastal mud flats and wet grasslands. Increasingly however, their journeys come to an abrupt end. Their natural food sources are destroyed by humans, they are hit by hunters' bullets and, biologists fear, their breeding and foraging grounds may be flooded as global warming leads to higher sea levels.

Questions

In anticipation of these problems and in order to come up with effective measures, biologists need to know more about these birds. Where exactly do they breed and what do they eat? Which migration route do they take? Where do they stop and rest? Schekkerman and Tulp are trying to find some answers, and their search took them to the Taimyr area of northern Siberia.

Schekkerman: "I spent a total of two months together with other Dutch and Russian Researchers in Taimyr, investigating the numerous wading birds that spend the summer here. The work is quite heavy going. It is cold, between zero and ten degrees Celsius, sometimes with strong winds. We wanted to find out what exactly the birds eat and how the food supply varies through the summer. This is very important for their survival." Before the birds take off to a more southern region, escaping the dark and very cold winter here, the birds need to build up large food reserves, he says.

Peak periods

After following the birds every day through the Arctic summer from June to the end of August, the biologist discovered that the birds are dependent on insects. "They need to arrive at their home grounds at exactly the right time since the number of insects peaks for only a short period in summer. If the birds miss this period, for example because they leave western Europe too late, the chicks may not find sufficient food in Siberia, and then they will be in trouble," says Schekkerman.

He says that migrating birds are dependent on many fluctuating factors like food supply, and every delay in their journeys can have negative consequences for their survival. When humans destroy feeding grounds in one area, while this might not have direct consequences, the indirect ones can be considerable. The birds stay longer in one area to gain weight, but then they may arrive too late in the area where they spend the other half of the year, miss the optimal food supply and may not be able to breed or even survive another year. So when birds die in one area, the cause may lie in an area thousands of kilometres away.

Schekkerman concludes: "We can only protect migrating birds by taking an international perspective. " As birds do not stop at country borders, nature conservationists should not do so either.

Hugo Bouter

Re:ageer