Studying Sandhill Cranes

Experts Count On Cranes, River System for Information

Story by
Heather Hooper

Photos by
Barrett Stinson

Article taken from The Grand Island Independent, Sunday, April 12, 1998

When Dave Brandt and his colleagues go out to the field, it looks like a military exercise. The men wear camouflage, lie hidden on the ground and speak to each other by handheld radios. They search the fields with binoculars, waiting for the moment when their target is within range. When all is right, they give the signal, and Brandt pulls the lever. A rocket-launched net flies into the air and settles over sandhill cranes. Brandt and other wildlife technicians from the U.S. Geological Survey office in Jamestown, N.D., have been trapping cranes this spring and fitting them with radio and satellite transmitters. The work is part of a five-year study of the Platte River system and the various factors that impact cranes.

Fifteen birds were fitted with radio transmitter bands, and five were fitted with satellite transmitter bands on their legs. The latter group will be tracked as it flies north to the arctic nesting grounds. The goal of the study is to provide information to wildlife managers on the cranes' needs so both the birds and the Platte River can be best managed, said Gary Krapu, wildlife biologist and project leader from Jamestown, N.D. Krapu ordered the study after conducting autopsies on several cranes following a March 1996 blizzard in Central Nebraska. About 2,000 cranes died in the storm from strong winds and deep snow. Many of the larger cranes had less than half the fat supply that was expected by that time in the season, he said.

Three sandhill cranes try to evade a rocket-powered net as it passes over them. Dave Brandt and other wildlife technicians have been trapping cranes this spring and fitting them with radio and satellite transmitters.

U.S. Geological Survey wildlife technician Dave Brandt carefully lifts an adolescent sandhill crane from inside the net.

The main reason for the month-long stop in Central Nebraska is for the cranes to build up a store of body fat to prepare them for breeding and nesting in the northern climate. Causes for fat loss are only speculative at this time, Krapu said. Many environmental impacts - including river channel characteristics, the population boom of snow geese and the habits of the cranes themselves - will be studied to determine the overall health of the crane population. One of the main factors being studied is the introduction of snow geese to the area. Krapu said that, when he conducted a crane study 20 years ago, there were no snow geese in Central Nebraska during the spring migration.

Today there are about 500,000 snow geese, as well as thousands of Canada and white-fronted geese. Part of the change has been in the snow geese migration pattern, and part has been a population explosion among the snow geese. Snow geese are "having an impact, but we don't know how they are impacting cranes," Krapu said. Another possible factor is the loss of river channel habitat, which has caused the cranes to become more crowded on the river, Krapu said. Crowding causes increased competition for food. Sandhill cranes used to spread further west along the river. Today, the majority settle in a 50-mile stretch between Kearney and Grand Island. Changes to the river are not new. Most of the major changes began in the 1940s when large water projects, such as Kingsley Dam, began to divert water from the river. Krapu said the cranes have been able to adapt because of the high amounts of waste corn in area fields. The study will emphasize how to best manage existing river flows to create the type of habitat needed for the cranes as well as other waterfowl.

Too young to fit with a radio and satellite transmitter, U.S. Geological Survey wildlife technician Dave Brandt sets an adolescent sandhill crane free.

Technicians will follow the banded cranes in specially equipped trucks through mid-April. They will follow the cranes' movements around the Platte River Valley to determine how far from the river they fly for food and how much they eat in various fields. Five other birds fitted with satellite transmitters will be tracked year-round from the arctic to the Gulf of Mexico. Although biologists know in general terms where the birds go, there is not much specific information about where each of the three sub-species of cranes nests and spends its winter. That type of information is important for management of the cranes, Krapu said. It can tell biologists if one group of the cranes needs more help than others. Researchers will be in Central Nebraska tracking the cranes from east of Grand Island to Overton through mid-April. They will be back next spring to continue the study, and to band up to 100 more birds.

Placing the "Judas crane" away from a group of other sandhill crane decoys, U.S. Geological Survey wildlife technician Dave Brandt hopes that the real birds will land in between the lone decoy and the group placing them in the best position for capture with the net.
	U.S. Geological Survey wildlife technicians Skip Stonesifer (left) and Dave Brandt carry about 10 sandhill crane decoys out to a field east of Grand Island in an effort to capture real sandhill cranes.