Radio
Telemetry: Tracking the Cranes
Every
Whooping Crane in the new Eastern flock wears
a leg band with a radio-tracking transmitter attached. Transmitters
send out signals so the WCEP team can track the birds. The process
of remotely
sending signals over a distance in order to
record information is called telemetry. In radio
telemetry, transmitters send signals that can be picked up
by a special receiver used by trackers. The receiver
collects and amplifies the signals so trackers can hear them.
Radio-tracking was developed by wildlife biologists and electronic
experts. Trackers use a radio receiver and directional
antenna to trace
the source
of a signal coming from a radio transmitter attached to the bird. By
dialing a certain setting on the receiver, the researcher hears a beep
when the crane is within range. Sometimes the trackers walk
on the ground, carrying an antenna to pick up the radio signals. Other
times they drive vehicles equipped with a big radio antenna on the
roof. They can track from an airplane, too. To hear more, click
on tracker
Lara Fondow's video clip, or read Lara's words below.
Text
of Lara's Video Clip:
"Hi,
kids. My name is Lara and I work for the International
Crane Foundation and my job on this project is to keep
track of
the birds once they are free flying. What I use is this radio
receiver and this antenna [see photo above].
I turn this on and each bird on their leg has a little radio
transmitter. And if I dial in the frequency on my receiver— just
like you would dial in the frequency of your favorite radio
station)—then I can pick up the signal of my bird. The
closer I get to the bird, the louder the signal is. And that's
how I can find the birds. If the bird is on the ground and
I'm on the ground, I can hear the signal if I'm less than 3
miles away from the bird. If the bird is flying, I can hear
for about 15 or 20 miles."
NOTE:
When Lara is in a plane and the bird is also in the
air, she can hear
the signals for a hundred miles or more. If The tracker in the
plane and the bird is on the ground, the signal distance is
about
7 miles. |
|
radio receiver |
|
tracking
van with
directional antenna
Photos
Wayne Kryduba |
|
|
|
Click
to enlarge. Do you
see the antenna on the
birds' legs?
|
Transmitters
and antenna on 2003 snap-on leg bands designed by Dr.
Richard Urbanek. The
radio antenna is about 9 inches long and weighs 60 grams.
It points
toward the ground. |
Chick
from HY 2003 with new leg band/radio transmitter.
Photos OM, WCEP |
Try
This! Journal or Discussion Questions
- The
entire transmitter unit weighs about 60 grams, and half the weight
is
the battery. The young cranes weigh around 14-16 pounds.
1.
What percentage of of a crane's weight is the transmitter?
2. What percentage of your own weight would a transmitter be?
-
How
would you like to wear a device that tracks you 24 hours a day, 7
days a week? Explain.
Journey North is pleased to feature this educational
adventure made possible by the Whooping
Crane Eastern Partnership (WCEP).
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