by Jason Abraham SEPTEMBER-OCTOBER 2005

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2 SEPTEMBER-OCTOBER 2005 by Jason Abraham

3 am - *, «s. S Wmmm^ The Nature Conservancy of Minnesota donated the first land for the 35,ooo-acfe Glacial Ridge National Wildlife Refuge, established last fall. Working with the DNR and other partners, the Conservancy initiated the nation's largest tallgrass and wetland restoration project there in northwestern Minnesota. THE NATURE CONSERVANCY n two days John Solberg will be in Ihis element flying a Cessna 185 single-engine airplane low and slow over prairie wetlands in the eastern Dakotas, counting ducks and geese as they pair off to bring a new generation of waterfowl into the world. But on this last Friday of April, he's in his office in Bismarck, N.D., sorting through papers, testing laptop computers, and assembling a small collection of fire-retardant flight suits. The U.S. Fish and Wildlife Service pilotbiologist is preparing for the coming three weeks, in which he'll fly about 5,000 of the Jason Abraham is a staff writerfor the DNR divisions of Ecological Services and Fish and Wildlife. 54,000 miles covered by the North American May Waterfowl Breeding Population and Habitat Survey believed to be the most extensive and comprehensive long-term annual wildlife survey in the world. For each of the past 50 years, the endeavor to estimate North America's breeding waterfowl population has played out in the skies above waterfowl breeding grounds in Canada and the northern United States. During the survey, USFWS pilot-biologists visit 2 million square miles of isolated prairie ponds, flying about 150 feet above the ground and counting waterfowl. Last year's breeding waterfowl population estimate for the traditional survey area, which includes portions of Canada, Montana, and the Dakotas, was about 32 million birds. That's down from the 50-year average of 33 million MINNESOTA CONSERVATION VOLUNTEER

4 Minnesota Spring Counts A Joint Effort Because the goal is to count breeding ducks where they are most abundant the prairie potholes of Montana, the Dakotas, and Canada none of Minnesota's duck habitat is included in the USFWS aerial survey. However, since the 1950s Minnesota biologists have conducted aerial surveys in the spring to assess local waterfowl populations and guide decisions on habitat management. In 1968 the state adopted federal survey standards, and the USFWS began incorporating Minnesota data on mallards, blue-winged teal, and total ducks into the spring breeding report. "It was a joint decision. The feds realized that our data would be valuable to the survey, and we realized the value in getting federal assistance,"says Bob Jessen, who was then a waterfowl specialist with the Minnesota Department of Conservation. "Even today, the state does the aerial portion of the survey while the ground crews are federal staff." Steve Cordts, a DNR waterfowl specialist based in Bemidji, today flies the same 125 routes in Minnesota that Jessen once flew. Minnesota biologists fly with conservation officer pilots, who also count and identify ducks. "Getting a bird's-eye view of the conditions is really Helpful in making management recommendations," says Cordts. "It's the only way to get a real feel for the amount and quality of habitat that's out there." (See Wetlands Watch, page 23.) u Q CT> C. 1/1 "D-o oi c OJ S Mil" IT I II II I I I I I I! 'I M i l l Year Estimated population Long-term average Minnesota began estimating waterfowl breeding populations in Over that lone term, annual duck r, r,,, ^,, abundance averaged 630,000. The 2005 count ot 632,000 was the lowest since the drought years in the 1980s. SEPTEMBER-OCTOBER

5 Canvasbacks soar in search of a wetland rest stop. In 2005 the estimate for breeding canvasbacks in Minnesota was down more than 70 percent from the previous year. BILL MARCHEL Spring Counts the count begins in early May. Pilotbiologists usually finish their routes by early June. State biologists in Minnesota, Michigan, and Wisconsin also conduct aerial surveys about the same time. The USFWS Division of Migratory Bird Management compiles all of the data from federal and state biologists into an annual report. Federal biologists use the aerial survey data to create the framework within which state agencies may select their waterfowl season length and bag limits. When waterfowl populations are low due to poor wetland conditions, wildlife managers shorten seasons and reduce bag limits to reduce harvest. "The breeding waterfowl data set is the envy of biologists all over the world," Solberg says. "It's very rewarding to know the numbers generated from our data will help perpetuate migratory waterfowl." During the past five decades, the aerial survey data have shown the resiliency of North American waterfowl populations, says Ray Norrgard, wetland wildlife program consultant for the Department of Natural Resources. "When the prairies are dry, the numbers dip," he says. "But when there's rain and grass, the ducks come back. "The good news is that since the mid- 1990s, we've had good rainfall and adequate habitat due to land protection through federal and state agencies, as well as the Conservation Reserve Program," Norrgard says. "The bad news is that we could have absolutely incredible duck numbers if we'd had better habitat." 14 8 MINNESOTA CONSERVATION VOLUNTEER

6 Fall Questions In 2005 Minnesota's breeding duck survey estimated 632,000 ducks, excluding scaup. Though roughly equal to the longterm average of 630,000, the abundance of ducks decreased 34 percent from 2004 and 10 percent from the 10-year average. The 2004 survey tallied about 1 million ducks, yet hunters last year suffered through one of the worst duck seasons in history. As many duck hunters found out, the number of breeding ducks doesn't necessarily correspond to hunters' success everywhere. Although the statewide duck harvest continues to rank among the top 10 nationally, hunters in western Minnesota say they're not seeing the duck numbers they once did. Researchers say the spring survey can't predict hunting success locally. Fall weather and local habitat conditions determine where and when hunters bag ducks and geese, says Ken Gamble, Mississippi Flyway representative for the USFWS. "It's kind of a game of expectations," he says. "Hunters see a high number of breeding ducks in the survey, long seasons, and liberal bag limits. Naturally, they expect to see ducks in the fall. Unfortunately, however, local hunting conditions sometimes don't match the expectations." While some hunters have questioned the survey's accuracy, researchers and pilotbiologists uniformly support the data. They point to scientific reviews that reaffirmed survey techniques and statistical accuracy in each of the past three decades. While the USFWS counts the annual waterfowl breeding population, additional surveys track duck harvest numbers. Minnesota's share of the Mississippi Flyway harvest has shrunk from one-sixth in the 1970s to about one-tenth today. QJ > C So.2 X = fr =3 C CJ 0 I I I II I II I II I II I I M II I I I I I I I I I I II I I i i i m M M i Year Mississippi Flyway Duck Harvest Minnesota Duck Harvest SEPTEMBER-OCTOBER

7 Aerial Surveys Unchanged Since 1955 Under the Migratory Bird Treaty Act of 1918, the USFWS and Canadian Wildlife Service began setting seasons and bag limits for migratory game birds in their respective countries. Eventually, aerial surveys provided the means for accurate counts for setting sustainable harvest limits. At the end of World War II, the USFWS acquired a fleet of airplanes and hired militarytrained pilots with experience in wildlife management, says retired USFWS biologist Art Hawkins. In 1946, Hawkins began working at Delta Waterfowl and Wetlands Research Station in Manitoba. Led by director Al Hochbaum, Hawkins and his colleagues developed a method to accurately estimate the continent's waterfowl population by counting ducks on spring breeding grounds. For eight years the team experimented to find the safest, most reliable altitudes and airspeeds for counting ducks. And they established aerial survey routes. In 1955 the USFWS and its Canadian counterparts launched the first coordinated waterfowl breeding survey. Today pilot-biologists fly the same survey routes. "We're sampling about 1 percent of the total breeding ground," says Hawkins. "But with that sample, we can estimate how many wetlands there are per square mile in each unit. Also, we can estimate how many ducks we saw on a given type of wetland. From that, we can build a statistical estimate of the waterfowl population for the whole breeding ground." He adds, "The whole purpose is to not change. To best compare the past to the present, we fly the same routes and look at the same area year after year." Still, the disconnect between hunter experiences and survey data is troublesome, says Norrgard. "This isn't easily explained," he says. "We believe the ducks exist, but population data isn't gathered after the spring survey, so it's very difficult to say where ducks are going during the hunting season, from a scientific standpoint." The DNR in Minnesota and other states are considering proposals to gather data on waterfowl in late summer or early fall. One possible explanation for fewer fall ducks, says USFWS biologist Khristi Wilkins, is hunting pressure, which is significant in Minnesota, a state that regularly ranks in the top five for active waterfowl hunters. "Ducks are wary creatures," Wilkins says, "They tend to seek out areas where they receive little or no hunting pressure." Test of Time major changes to the USFWS survey areas are unlikely, though improvements in satellite imagery or the use of unmanned aircraft could someday help expand the survey into remote areas that currently aren't covered. For now, hunters and wildlife managers alike will count on pilot-biologists like Solberg to keep flying the traditional routes that provide an annual view of North American breeding waterfowl populations. "It's like following in the exact footsteps of the great waterfowl pioneers," says Solberg. "We might use computers and GPS, but it's very much the same process. The fact that this survey has stood the test of time says a lot about the people who designed it, as well as the hundreds of people who continue to i work to maintain and improve it." MINNESOTA CONSERVATION VOLUNTEER

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