May 30, 2013
SAUVIE ISLAND, Ore. – It’s 5 a.m. and a dozen fish and wildlife biologists clad in camouflage quietly crouch in the brush next to a field of corn stocks hiding them from tens of thousands of cackling Canada geese in an adjacent field.
Quietly and patiently these men and women wait as darkness turns to dawn over the Sauvie Island Wildlife Area (SIWA). All are being careful not to spook the birds and drive them away, which would prolong the early morning routine. ODFW wildlife biologist Tod Lum – the “trigger man” – closely watches and waits for hundreds of geese to move toward the empty corn stocks shrouding three 60x30 ft. “rocket nets” lying on the ground. When the moment is right he will push the red button on the box in his left hand, sending a low voltage electrical charge down a thin yellow wire to a row of rockets that will lift the nets up and over the birds.
As dawn turns to daylight, five geese circle in from above, land, and start devouring the corn, millet and buckwheat bait sprinkled around the net to draw them in. Ten more geese circle, descend and land to join the others in their morning meal. Then another 20, then 50, then 100 touch down and join the march to free food. Suddenly the sky turns black with descending cacklers anxious to join the party before the food is gone.
At first, the geese are wary but oblivious to the net while their eventual captors wait in the wings with leg bands and neck collars. Later in the morning, these markers will be clamped and glued onto the birds as part of a population study involving half a dozen wildlife agencies from Alaska to California, all members of an international coalition of wildlife agencies known as the Pacific Flyway Council. The birds quickly become so focused on consuming everything in their path they disregard the net just a few feet away … until the moment of truth.
“Three, two, one,” Lum whispers over the radio, alerting his colleagues to the ensuing frenzy that will begin as soon as he launches the rockets.
The net lifts skyward shrouded by a billowing cloud of white smoke which floats over the ground for a couple of minutes. The sky again turns black with geese, only this time the birds are taking off en masse. As the smoke clears, human figures appear from the edges of the field, running toward the net, which now covers a hundred geese and a few ducks.
Working quickly and purposefully, biologists and technicians from the Oregon and Washington departments of fish and wildlife, along with U.S. Fish and Wildlife Service biologists and a handful of volunteers, carefully remove the birds from underneath the net and gently place them into small bags. The bags to keep them calm and safe until they can be removed so small metal bands can be put on their legs and bright yellow plastic collars slipped around their necks. While biologists handle the birds, technicians record their data -- age, sex, band number, and collar code. Inscribed on each metal leg band is a unique number that can be called in by hunters who harvest one of the birds in the future. The bright yellow plastic neck collars also have a unique code but are larger so they can be read from the field while the birds are still alive during annual population surveys.
This scenario – netting, banding, collaring and releasing birds – was repeated for seven days and leg bands and neck collars were placed on 558 geese that were subsequently released to continue their journeys to summer breeding grounds on the Yukon-Kuskokwim Delta in western Alaska.
This is the start of the third year of a three-year study to reassess the cackling Canada geese population size in the Pacific Flyway, a major north-south route of travel for migratory birds in western North America, extending from Alaska to Patagonia. Biologists will use the information gathered during this study to help guide future management decisions.
During the mid-1990s most cackling Canada geese switched their wintering grounds from the Central Valley of California to Oregon’s Willamette Valley, Sauvie Island, the lower Columbia River and adjacent areas of Washington. The birds are now causing significant agricultural crop damage in these areas. Sauvie Island, located at the confluence of the Columbia and Willamette rivers about 10 miles west of Portland, is a major stopping point for geese during their migration along the Flyway, sometimes hosting as many as 50,000 geese at a time. The 11,500-acre wildlife area is owned by ODFW. The agency manages approximately 4,800 acres of wetlands, 2,200 acres of pasture/grassland habitat and more than 1,000 acres of corn, millet, buckwheat and winter wheat for waterfowl and other wildlife. This management program provides considerable forage for wintering Canada geese and helps alleviate damage to adjacent farm fields.
“Some questions have come up among members of the Flyway about the accuracy of current methods used to estimate the size of the cackling Canada goose population,” said Brandon Reishus, ODFW Migratory Game Bird Program coordinator. “In the end this study should tell us with pretty good precision how many cacklers we have. At that point, the Flyway can begin revising its cackling goose management plan but we can’t take any new management actions with the uncertainty that we have about the population right now.”
The population study will enter its final phase this summer with the banding and collaring of additional cackling Canada geese in Alaska. Biologists and technicians will then survey for and record neck collar information over the course of the next fall, winter and spring.
“This is a total Pacific Flyway project,” Reishus noted.
Agency partners in the population study include the U.S. Fish and Wildlife Service, U.S. Geological Survey, Alaska Dept. of Fish and Game, Washington Dept. of Fish and Wildlife, California Dept. of Fish and Wildlife, Canadian Wildlife Service and Pacific Flyway Council.