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USGS and Partners to Evaluate Impact of Habitat Restoration on Migratory Waterfowl in the Central Valley of California
Released: 12/17/1998

Contact Information:
U.S. Department of the Interior, U.S. Geological Survey
Office of Communication
119 National Center
Reston, VA 20192
Gloria Maender 1-click interview
Phone: 520-670-6896 x1

Joe Fleskes
Phone: 707-678-0682 x628

Dennis Orthmeyer
Phone: 707-678-0682 x626

NOTE TO NEWS EDITORS: Reproducible photos may be found at:
http://biology.usgs.gov/pr/newsrelease/1998/12-17a.tif (truck with radio-tracking antennae)
http://biology.usgs.gov/pr/newsrelease/1998/12-17b.tif (rocket net)
http://biology.usgs.gov/pr/newsrelease/1998/12-17c.tif (pintail duck with radio transmitter)
http://biology.usgs.gov/pr/newsrelease/1998/12-17d.tif (released pintail with radio transmitter)

Sitting in the darkened cab of a pick-up truck on a California Central Valley back road, research biologist Joe Fleskes of the USGS Western Ecological Research Center strained to hear the faint "beep beep beep" from his radio-tracking receiver. Somewhere out in the foggy night, the radio signal was emanating from a small transmitter worn by one of 320 ducks and geese fitted with these monitoring devices.

By radio-tracking the birds, Evaluation Project Leader Fleskes and more than a dozen other researchers hope to learn during the next three years what waterfowl do during the day and night throughout the winter. Monitoring waterfowl movements is just one part of a large cooperative research effort to discover what effect ten years of habitat restoration, preservation and management have had on waterfowl wintering in the Central Valley. Information gathered on the lives of ducks and geese in this project of the USGS, the U.S. Fish and Wildlife Service (USFWS), the California Department of Fish and Game, Ducks Unlimited, Inc., the California Waterfowl Association, and the Grassland Water District will help wildlife managers judge whether the goals and strategies of Central Valley habitat programs are appropriate or need to be modified.

"Why do we care what ducks and geese do at night?" asked Fleskes. "Many waterfowl, especially ducks, feed primarily at night. If we observed them by day only, we would only know where they roosted -- or slept. We’d have no idea where they go to eat. To evaluate our habitat programs, we need to know where these wintering birds spend both their days and nights."

Whether duck or goose, said Fleskes, the waterfowl may move about in search of choice locations for both feeding and sleeping. These two principal activities often do not occur at the same location and waterfowl may expend considerable energy in travel between sites.

"If a bird must fly a long distance to find food or a safe roost throughout the winter," said Fleskes, "it will be less fit when it returns to its nesting grounds in the northern United States or Canada. It may produce fewer young, or fail to reproduce."

Fleskes said the study will provide information on the kinds of habitats wintering waterfowl select for feeding and roosting. It will also indicate how the location and management of habitats affect their use. Biologists in trucks equipped with cab-mounted directional antennae and specialized receivers to pick up transmitter frequencies will attempt to track each bird’s location around-the-clock until the birds migrate north in the spring.

Despite wetland losses of over 90 percent in this century, the Central Valley has remained one of the most important areas for migratory waterfowl in North America. Remaining wetlands, flooded agricultural fields, and wildlife refuges from Redding to Bakersfield provide a winter home to 60 percent of the ducks and geese that migrate along the Pacific Flyway, 20 percent of all North American waterfowl.

Fleskes noted that federal, state and private wildlife managers in the Central Valley have long been active in trying to preserve and increase the quality of waterfowl habitat. Since 1988 the Central Valley Habitat Joint Venture (CVHJV), under the auspices of the North American Waterfowl Management Plan, has been restoring and preserving habitat and implementing changes in farming practices to reverse past habitat losses and prevent additional loss.

To evaluate the impacts of the CVHJV restoration efforts in the Central Valley on migratory waterfowl, USGS scientists will compare the tracking data they collect during the current project with historical information gathered before CVHJV habitat changes began. The USGS Western Ecological Research Center has radio-tracking and aerial survey information on northern pintails and white-fronted geese that date from 1978 through the 1980’s. Similar data for mallards were collected by the California Waterfowl Association.

Field work for the current project started in August 1998 in Alaska and the Central Valley. In Alaska, 60 molting and flightless white-fronted geese were herded into corrals and fitted with radio transmitters by Craig Ely of the USGS Alaska Biological Science Center and Mike Wege of the USFWS. By 15 November more than 50 of these geese had made their way to the Central Valley. Ducks were captured in the Central Valley after they had migrated from their northern breeding areas. During late August and September biologists of the Western Ecological Research Center captured 150 northern pintails, 50 mallards and 60 green-winged teal, using rocket-propelled nets. Once measured and fitted with small radio transmitters, the ducks were released at the capture site.

"Each of the 320 ducks and geese that are wearing radio transmitters has a distinct frequency," said USGS scientist and White-fronted Goose Project Leader Dennis Orthmeyer. "Locating each radio-marked bird is like tuning the AM dial in your car or truck. Radio stations have different frequencies, but instead of tuning in to your favorite country and western station, you might be picking up the frequency of a white-fronted goose banded and radio-marked at the start of the season."

More than a dozen trackers are working the entire Central Valley this winter, with ground crews in the northern Sacramento Valley, the Sacramento-San Joaquin Valley River Delta, the southern San Joaquin Valley and locations between. A small airplane equipped with antennae is flown periodically to search for birds that ground crews can’t locate.

"On the ground, we are limited to less than three kilometers, but in the air, we can hear a frequency 40 kilometers away," said Orthmeyer. "A bird that hasn’t been found for several days may have moved outside the range of the tracker’s receiver."

A change in radio transmission can tell scientists if a goose or duck has died, important information for the study. The researchers also hope for cooperation from the public. They ask that anyone who finds or shoots a radio-marked bird call Joe Fleskes or Dennis Orthmeyer in Dixon, California, at 707-678-0682, extensions 628 and 626. Callers are welcome to keep the radio-transmitter and will receive a history of movements made by their bird.

In April the ducks and geese will leave California and the beeping will stop until fall, when another 320 birds will be fitted with new radio transmitters. Until then, Fleskes and the other researchers will be busy analyzing the data collected this winter.

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