from the Sky: About Those PTTs
anyone's guess as to when the ultralight chicks will start their first
journey north. What path will they follow? Will
they use safe crane habitat along the way? Crane trackers have help
finding out, thanks to the Platform
Transmitter Terminals (PTTs) on some of them.
The tracking team follows the migrating birds in vehicles equipped
with radio receivers.
As soon as the young birds head north, ICF trackers hit the road,
tracking the youngest birds of the new Eastern flock.
Powered by Batteries
PTT is powered by a battery. Because the battery wears down each time
it's used, the PTT can't constantly send signals. Experts program the
battery to send a specific radio signal according to a schedule set by
the WCEP scientists.
example, the cranes' PTT batteries run 8 hours on a given transmission
day. The "duty cycle" affects how long the battery will last.
On the current schedule, the batteries in the crane PTTs will probably
last at least 750 hours, says project biologist Dr. Richard Urbanek. "But
no one would be surprised if the antennae broke off before then and the
units stop working", he adds.
Platform Transmitter Terminal is
a satellite tracking device that can be worn/carried by an animal
so its position is known.
do you think the name and address of Operation Migration is
on the PTT?
The PTT is
light, so it does not hinder the survival prospects for the bird. The
bands and transmitters stay on the birds for life. The bands that support
the transmitters are part of the color-banding scheme. They are used
individually identify the birds. These bands are fastened securely so
that we can identify the birds throughout their lives, even after the
Do the Units Affect the Cranes?
#208 with PTT on his right leg and
radio transmitter on the left leg (red/white).
Photo Sara Zimorski
preen it and pick at it, treating it like any other accessory. Of
they'd like to be rid of it if they could," said ICF's Anne Lacey,
who monitored the 2001 chicks in Florida. "Over
the years many birds like cranes have been fitted with PTT’s.
Other than a problem with ice forming on the antennas, the PTTs do not
to bother the birds once they get used to them. The birds will often
try to preen the antenna as if it is a feather that will not smooth
normally that's all that happens. So far we have not seen any problems
and they do not inhibit flight."
The units weigh 30 grams. They are designed
for mounting on a leg band for birds like cranes. One PTT costs approximately
$2800.00 plus the band and mounting, and the Argos costs.
Eyes in the Skies
The crane PTTs broadcast signals to the ARGOS/NASA satellite. According
to NOAA, the polar orbiters
do more than track migratory species. They are
the entire Earth, tracking atmospheric variables
and providing atmospheric data and cloud images. The cranes' signals
are picked up by polar-orbiting satellites when the satellites pass high
Imagine! Zipping through space, the same satellites are picking up signals
from other animals wearing transmitters — the manatees in sunny
Florida, the caribou
in the cold Arctic, and the bald eagles on the East Coast.
step back for a minute. Think about the information the satellite sends
every two days, and the assumptions we might be making when we interpret
the data. Now you're ready for our questions:
This! Journal or Discussion Questions
your eyes. Imagine being in your classroom, day and night, with your
eyes closed. Every 2 days, you blink your eyes open for a few seconds.
You ONLY have that time to see what is happening. The rest of the time,
you see nothing but darkness. As a class, consider the conclusions you
might draw, based on your limited observations. Think about that image
when you interpret satellite data. The satellite only sends a snapshot
representing a moment in time. Based on your discussions and what you
read above, list in your journal some benefits AND some limitations
of satellite tracking.
- The risk
to the birds would be high if anyone were to try and catch the bird
to replace the transmitter or recharge it, yet several captures and
replacements have taken place through the years of the flock's existence.
think the risk is worth the information that might be gained? Explain.
North is pleased to feature this educational adventure made possible
by the Whooping
Crane Eastern Partnership (WCEP).
Science Education Standards
used to gather data enhances accuracy and allows scientists to analyze
and quantify results of investigations.
help scientists make better observations, measurements, and equipment