Here in the opening years of the 21st century, hunters and waterfowl managers have come upon strange times. On one hand, we’re faced with the riddle of declining numbers of bluebills, black ducks, pintails, harlequins, and eiders. On the other, we’re struggling to deal with birds that are about to choke on their own success. Prominent among these are several populations of arctic-nesting geese.
The biologists short-hand them into a single group, the “light geese.” The term is deceptively simple–it includes two species, two subspecies, two color phases, and half a dozen distinct populations. All of them nest in the arctic tundra from the northwestern shore of Greenland to Wrangell Island off the coast of northern Siberia. In the fall, they retreat to warmer places from the Gulf coast to California’s Central Valley
Over the last 30 years, the light geese have happened on good times. The key has been a shift in agricultural practices from the Gulf to Canada’s aspen parklands. Everywhere the birds travel, it seems there is some obliging farmer setting the table.
On the Gulf coast where snow geese once fed on the tubers of wild slough grass, there are now rice fields. Farther up the migration routes, grain farmers have adopted minimum-till or no-till techniques–where there were once expanses of plowed fields, there is now crop stubble left over from the previous fall. The birds glean grain and graze on new shoots just coming up. Instead of losing weight on spring migration, they gain. When they arrive on the tundra, they’re in peak condition, ready to make a maximum breeding effort. [For more analysis on lesser snow geese, see the April-May 1997 and December-January 2000-2001 issues of WILDFOWL]
The long-term trends are astounding. In 1973, counts from the eastern Arctic–that’s Hudson’s Bay and points north–found a little over a million lesser snow geese. Biologists estimated that there were about 1.3 million snows in the region that year, including non-breeders. In 1997, the count showed about 3.9 million, a three-fold increase. Counts in the central Arctic are even more overwhelming. In 1976, there were about 73,000 lesser snows in the region; in 1998, there were more than a million, an increase of 1,400 percent.
As is so often the case with exploding populations, these geese are eating themselves out of house and home. The adults pack into their nesting colonies before green-up, hungry from a 3,500-mile trip. Since there is no new plant growth, they grub down into the mud after stems and roots, destroying plants before they have a chance to send up leaves. As the spring progresses, new shoots emerge, and the geese pull them up, root and all. Any grasses and sedges that survive into summer are heavily grazed.
The resulting mud flats absorb more sun than green vegetation would, so evaporation increases, pulling water up through the subsoil. Much of this subsoil is permeated with salt. As water rises through it, the salt dissolves and crystallizes as the water evaporates. The salt crust keeps most plants from growing, turning mud flats into desert. The damage could easily persist for centuries.
Habitat deterioration is well advanced along the western shore of Hudson’s Bay. Six years ago, biologists estimated that 35 percent of the salt marshes in the Hudson’s Bay lowlands had been destroyed, 30 percent was damaged, and 35 percent was overgrazed. The loss of the habitat affects other geese, ducks and shorebirds as well as the snow geese themselves.
Bruce Batt, chief biologist with Ducks Unlimited, has been following this trend with growing concern since the early 1990s when it was first reported. “None of us that have been involved from the beginning have any doubt in our mind that the ecosystems the geese are living in are being destroyed,” he says. “There’s a finite amount of that habitat–it will ultimately run out. At that point in time, the habitat that [the geese] use will be so impoverished that they will crash.”
The crash could come over the course of several years as breeding success declined, or it could happen overnight as the result of illness such as avian cholera.
Waterfowl managers recognized these risks in the early 1990s and have been trying to reduce light goose populations ever since. In the Atlantic, Mississippi, and Central flyways, hunting seasons on snow geese grew steadily longer until, in 1995, they reached the legal limit set by the Migratory Bird Treaty Act–107 days. Bag limits crept up as well. In 1994, the Atlantic Flyway had a federal limit of five light geese; by 1998, it had expanded to 15.
The increasingly liberal regs increased harvest. Estimated kill of lesser snows in the U.S. rose by seven percent from 1995 to 1996, by another six percent from 1996 to 1997, and a whopping thirty percent from 1997 to 1998. But it wasn’t enough. Winter estimates of the mid-continent population of light geese continued to increase as well–between 1993 and 1998, they more than doubled.
In 1997, Robert “Rocky” Rockwell, a biologist with the American Museum of Natural History, teamed with two other specialists to figure out just how many geese would have to die to save the nesting grounds. The critical threshold was an annual harvest of 1.41 million light geese in the U.S. and Canada. If we could kill that many birds for eight or 10 years straight, there was a good chance of getting the population back under control.
Rockwell described it as “paying down a mortgage. In the first year of the mortgage, most of the payment goes to interest costs and little to reducing the principal. In subsequent years, increasing amounts go towards the principal.”
Waterfowl managers had to find a way to increase “the payment,” which was a challenge since they were already allowing a 107-day season with double-digit limits. In 1998, they proposed a “conservation order” that would allow spring hunting with electronic calls in 1999. A legal battle with animal rights groups stymied the new regulations, but Congress intervened, passing a law that allowed the spring hunt until an environmental impact statement could be drafted. The “conservation hunt” began in the spring of 1999, catching the birds on their northward migration. Electronic calls were legal for the special hunt; there were no bag limits, and shooters didn’t have to buy duck stamps.
The biologists crossed their fingers: Would it be enough? We have four years of harvest estimates in hand, and there is still doubt.
In 1998-99, the first year of the conservation order, estimated harvest of light geese in Canada and the U.S. was 1,280,000 birds. In 1999-2000, there was great news: The harvest had risen to 1,550,000, exceeding the threshold of Rockwell’s model. And the winter counts of light geese in the mid-continent flock showed signs of decline. The flock on the western edge of the Central Flyway, however, showed a spike upward.
In 2000-2001, harvest estimates dropped to 1,020,000 birds; the winter estimate of mid-continent light geese
dropped slightly, and counts of the west-Central-Flyway birds plummeted. Optimism among the biologists was tempered by the knowledge that the winter counts sometimes miss significant numbers of birds and aren’t always trustworthy. Still, there was reason for hope.
In 2001-2002, the harvest estimate increased to 1,380,000. Winter counts of the west-Central-Flyway flock didn’t change much; winter counts of the mid-continent flock started up again.
So where are we with light geese? Rockwell is optimistic. Four years ago, he had this to say about the outlook: “Given the opportunity, hunters can easily exceed the target harvest. . .. The increased harvest not only will begin solving the problem but also will provide part of the data critical for monitoring the mid-continent population. . .. So, let’s just keep paying down the mortgage.”
Bruce Batt agrees. In this case, he sees waterfowlers as the best cure for what ails snows. “Hunters are the best conservationists,” he told me. “They work for nothing; they’re trained; they bring their own equipment; they’re motivated…. By the harvest, it looks like we’re having an impact.”
He goes on to say that the most important numbers in this management puzzle will probably start coming in next year.
“The only good count of these geese we get is the one that is done in June. It’s an aerial survey done by photography in which the birds are counted [every five years or so because of the area’s remote nature]…now, we’re trying to get another count. I don’t know what will happen when we get the inventory, but I think we’ll find that some of the colonies are actually leveled off or declining.”
It will be several years before we have definite information on snow goose populations and the condition of their breeding grounds. In the meantime, people who care about these birds can take up that strange exercise–we can help save the birds by shooting them. So keep the barrels hot and pay down the mortgage for the future health of these and other wildfowl.