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"Operation Crane Watch" allows those with computers and interested in wildlife to monitor the migration of sandhill cranes that have been equipped with satellite transmitters.

The small transmitters are attached to the cranes just above the knee joint.

A satellite transmitter is attached to the crane's upper leg.

Money is the limiting factor in how many cranes are being monitored as it costs about $3,800 per bird to get the desired data, says Gary Krapu, a biologist at the U.S. Geological Survey's Northern Prairie Wildlife Research Center at Jamestown, N.D. The Central Flyway states and the U.S. Fish and Wildlife Service are helping fund the study.

The transmitters are attached to the sandhill cranes in the Platte River Valley area of Nebraska, where the cranes stack up in spring on their northward migration.

Large, rocket-propelled nets are set in a crane loafing area, usually a pasture or grasslands. Several taxidermy-mounted sandhill crane decoys are used around the perimeter of the net to coax the cranes into the throw of the net. The decoys were made by Dale Marks, a farmer and taxidermist at Yipsilanti, N.D.

Dave Brandt removes a sandhill crane from the capture net. A crane decoy is in the foreground.

Krapu, who heads up the study, initiated a pilot study in 1998 to evaluate the satellite telemetry technology. Five cranes had transmitters attached. Sixteen more received transmitters this spring.

The nets are usually fired on small numbers of crane - like adult pairs or family groups - to reduce handling time and stress. Captured cranes are released at the same time to maintain potential pair and family bonds.

3 subspecies of cranes

There are three subspecies of sandhill crane - the lesser, which is the most numerous, the larger Canadian and greater sandhill crane in the mid-continental crane population.

Krapu said that biologist Dave Brandt, who runs the field operations, captured four lesser sandhill cranes and one of the Canadian race in March 1998. The five transmitter-equipped cranes were monitored as they migrated northward last spring and again last fall and this spring. The approximately 2-ounce transmitters last for about 15 months.

A wealth of information was learned from the five cranes, Krapu says. Two of the cranes migrated to northeast Russia, extending the known breeding range of sandhill cranes stopping at the Platte River in the spring. The other three cranes settled on breeding sites in parts of northern and central Canada.

Move 1,000 miles

In the fall, the cranes migrated to wintering grounds along the Gulf Coast and western Texas. Also, he said the birds were documented traveling a thousand miles or more between major stops. This flight pattern suggested the satellite transmitters were having little or no effect on the birds' movements.

The conclusion was supported by results from 10 cranes equipped with regular transmitters during March 1998. In March 1999, eight of the 10 with regular transmitters were relocated in the Platte River Valley and three had young providing further verification the technique was meeting needs.

Desktop tracking

By using satellite transmitters, the two biologists can literally sit at their desks and track the birds, unlike having to use planes and vehicles to track birds carrying regular transmitters.

Crane locations arrive at the Jamestown center daily via e-mail from ground-tracking stations run by Argos, a multi-national scientific body set up to handle data being collected using satellite telemetry.

Krapu says plans are to continue trapping and putting satellite transmitters on cranes for two more years. "Our goal is to get a total of 200 radio-transmitters funded. We have funding for about 75 to date."

The research project is designed to learn about the breeding, migration and wintering areas of the various species of sandhill cranes, which make up the world's largest crane population.

According to "Operation Crane Watch," Northern Prairie Research Center biologists have been studying the midcontinent population for the past several decades with a primary focus on population dynamics and the role of staging areas in their life cycle.

Goals of study

Among the goals of the study, says Krapu are:

• Delineate the breeding grounds, migration routes and wintering grounds of each of the three sandhill crane subspecies.
• Determine where the various sandhill crane subspecies are distributed at various times during the migration, thus being more able to target the more abundant lesser cranes during the hunting seasons up and down the flyway.
• Evaluate the Platte River Valley itself. The study will help evaluate areas of use, which have been shrinking, resulting in cranes becoming more and more concentrated and increasing the potential for disease outbreaks and shortages.

Once some of the questions are answered, it will be possible for more effectively target areas for habitat restoration in the Platte Valley.

There are about 550,000 sandhill cranes in the mid-continental population, which accounts for about 80 percent of all sandhill cranes.

The breeding range of the mid-continental sandhill cranes runs from Ontario north of Michigan to Siberia or northeast Russia, based on study findings to date.

There are two major spring and fall staging areas for arctic nesting cranes on the Canadian prairies in Saskatchewan, says Krapu. Once they leave western Saskatchewan in the spring, those nesting in Siberia move in long hops northwestward crossing the Bearing Strait to Siberia in less than a week. They also nest in Canada and Alaska.

Large numbers of sandhill cranes move through North Dakota on both the spring and fall migrations.

The cranes winter across a wide area from the Gulf Coast of Texas and through western Texas and eastern New Mexico.

To determine where a particular crane is at a given time, call up "Operation Crane Watch" on your computer web site: http://www.npwrc.usgs.gov/perm/cranemov/cranemov.htm.