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Radio telemetry runs on the same basic principles as the radio you listen to every day.
A small portable transmitter (radio station) emits radio waves, which are picked up by a
receiver through an antenna. Instead of transmitting the top forties or local rap
stations, the wildlife transmitters emit beeps. Each animal is given a separate frequency
(radio station number). Just like you can dial between stations, researchers can dial
between animals. Why can't you pick up these beeps on your radio? The frequencies (radio
station numbers) used by researchers are higher than can be received by your radio.
Using radio collars and telemetry equipment to follow or locate wildlife is not a new
technique. Over the years, many species of wildlife have been studied using radio tracking
devices. What is changing is the improvement in equipment. Early transmitters were large
and bulky. Only large animals such as bear, elk, and moose could easily wear these
Today, transmitters small enough to fit on the backs of songbirds or be
clipped to the wings of butterflies are now being used to
identify habitat use and gather information on migratory routes. Collars can even give
signals that tell when an animal has died. This is important and allows biologists to
quickly get to a site when the reason for the animal's death is important. Collar signals
are now strong enough to be picked up by satellites. Researchers can program data
collection based on an hourly, daily, or weekly movements.
In Michigan, radio telemetry has been used to monitor bear, moose and wolves
to gain more information on habitat type and food preferences and even to locate
denning sites. Small, temporary transmitters were
glued onto a tail feather of young osprey released in southern Michigan, making
it easier for osprey attendants to locate and identify the young as they fledged.
DNR researchers have used satellites to track collared Canada geese up to 2500
miles during their north-ward post-breeding "molt-migration."