Satellite Tracks Crane to Winter Quarters

As Karpalo the crane migrates south, a transmitter buried in its feathers keeps a group of Finns informed of its progress.

Radio signals bounce off a satellite to computers in France and the United States, telling the Finnish Crane Committee where the bird is, how often it flaps its wings and whether it’s pecking for food.

“If we get a zero pecking count for 24 hours, we know the bird is dead,” said Juhani Rinne, the committee chairman.

If Karpalo survives and the transmitter doesn’t break down, the Finns expect to solve an ornithological riddle: Where do Finnish cranes go for the winter?

Karpalo, a male, was born last summer in Jurva, west Finland, and named after the cranberry, a fruit that grows in the bogs where cranes nest. It is one of two young cranes to which the Finnish committee strapped 6-ounce radio devices.

Rinne said he believes it was the first European use of satellite bird tracking, a method developed by the International Crane Foundation in the United States. The Finnish project will cost an estimated $13,000.

A warm autumn delayed migrations, and Karpalo did not head south until late October. On Oct. 20, it was in southwester Finland, 135 miles from its birthplace.

A week later, Karpalo had flown 1,030 miles to the Hortobagy nature reserve, east of Budapest. The transmitter on the other crane failed after the bird reached Estonia.

Using a sensor that monitored Karpalo’s body movements, the Finnish committee estimated that the crane averaged 60 wing flaps a minute when it was in the air. It made 87,000 flaps during the flight to Hungary.

To save batteries, the transmitter turned itself on only for four hours every third day. Rinne expected the batteries to last a year.

To locate the crane, the Finns used a technique of measuring radio frequency shifts that is familiar to sailors. The shifts showed the bird’s distance from a satellite. Readings involving two satellites gave a position fix.

European cranes, like those in Finland, have been able to adapt to human populations and are not among the world’s most threatened species. But Rinne said finding the cranes’ winter quarters could help conservationists to extend protection to the birds.

Rinne said he believes Karpalo will wind up in northern Africa.

“Cranes from Sweden spend the winter in southern Spain and cranes from the Volga bend (in Siberia) have been found in countries like Iran and Israel,” he said. “My guess is our cranes will turn from their straight southerly course soon and go to Tunisia.”