Raptor center does high-tech tracking

by Kari Siegle

Two Minnesota ospreys wintering in South America may not know it, but University researchers are watching the birds’ every move via satellite.
The raptor center at the University is tracking two ospreys and their seasonal migration to Central and South America. After two years, researchers said they hope to find exactly what routes the birds take and where they spend the winter.
There are about 400 pairs of nesting osprey in Minnesota, and during the warm months they live along the northern lakes and the St. Croix River. The birds mainly eat fish and are noted for their white heads and black eye-stripes.
“The technology is really stepping us into a whole new ability to learn (the osprey’s) locations,” said Mark Martell, coordinator of raptor center conservation programs. This is the first time the raptor center has used the satellite technology on any of its birds.
The raptor center caught an adult female and adult male osprey, which are not mates, in Carver Park in August 1995.
Using Teflon-coated nylon straps, researchers placed small backpacks containing satellite transmitters and batteries on the ospreys’ backs.
The backpacks weigh about 30 grams — or as much as a business letter — and are not noticed by the birds.
The transmitters relay the birds’ locations to two satellites. The satellites pick up the signals, calculate the locations and send the information to receiving stations around the world. Then Martell gets an e-mail containing the ospreys’ coordinates from the posts.
The ospreys’ transmitter batteries are good for 500 hours. In order to stretch out the time, the packs send a signal and Martell gets an e-mail every 10 days during winter.
In the spring and fall months, when the birds travel more, Martell received an e-mail every three days.
Martell said he was surprised to find that the two birds took different paths south and departed at different times. The female left before the male and flew straight south to Bolivia, where she has stayed since October.
The male left two weeks after the female and went southeast through Florida and is now on the coast of Colombia by the Caribbean Sea.
“These birds nest no more than a mile apart, and they’re wintering hundreds of miles apart,” Martell said.
As soon as he receives the e-mail with the ospreys’ locations, Martell puts it on a World Wide Web page designed for the public — especially schoolchildren — to follow the birds.
The web page is part of the “Highway to the Tropics” educational research project funded in July 1995 by the Minnesota Legislature. The raptor center received $250,000 to pay for the transmitters, which cost $3,000 each, and other costs.
“Environ-mental education often teaches kids today about answers, but not the ways scientists get the answers,” said Michael Kennedy, Raptor Center educational specialist.
“It’s a species everyone in the world can relate to because it’s found everywhere,” he said. Ospreys are found on every continent except Antarctica.
Kennedy said studying osprey migration is a chance for kids to learn that what happens in a natural environment doesn’t follow political boundaries.
Martell said usually information is collected, organized, analyzed and published. But in this situation it’s shown in raw form to the public. “It kind of flies in the face of what we normally do with data,” Martell said.
This summer, the center will put backpacks on another 10 ospreys. Martell said there are also plans to study the birds’ migration from the states of Washington and New York.