White Geese, Blue Geese...
And Lots of Them

Photo by Daphne Kinzler

 

By Craig Bihrle
Sept.-Oct., 1992



In addition to nasty weather, snow goose hunters are generally more successful when the flocks that come through North Dakota each fall contain a good number of young-of-the-year birds. The young ones are suckers for a good decoy setup, while the old birds, well, you'd wise up too if you'd seen decoy sets from September through January every year for a half dozen or more trips up and down the Central Flyway.

Based on reports from the Canadian arctic, where snow geese nest and raise their goslings, there won't be an abundance of those gullible young birds coming through North Dakota this fall. There will, however, be excellent numbers of those cagey old adult birds, the ones that even in a blinding sleet storm know a con job when they see one.

Hunters who are able to lure in, get under, or sneak up on snow geese this fall will be able to take advantage of the most liberal duck or goose limit this country has seen in quite some time. The daily snow goose limit has been raised to 10, up from seven the last two years, and five before that.

It might seem odd that the snow goose limit has been upped again, especially in light of poor production this summer. After all, for most game bird species, limits are liberalized when production is good, and they are cut back when production is poor.

The mid-continent snow goose population, however, is an exception to that rule. The population of these birds has grown too large for its own good. If hunters can't harvest enough of these birds, it may only be a matter of time before nature brings in disease and starvation to stymie the burgeoning snow goose population.

It makes for an interesting story.

The Mid-Continent Population of Snow Geese

There are four separate populations of snow geese that migrate up and down North America each fall and spring. The birds that migrate through, and stage in North Dakota each fall and spring are called the mid-continent population. The mid-continent population is a group of snow geese that nests on the west and northwest sides of Hudson Bay, northeasterly to Baffin Island, and then westerly along the southern shores of the Arctic Ocean (see figure).

Mid-continent snow geese stage primarily in southern Saskatchewan and Manitoba, and in North Dakota in the fall, before flying to traditional wintering grounds along the Gulf Coast of eastern Texas and western Louisiana. Rarely are these birds harvested in a state that does not border the dividing line between the Central and Mississippi flyways.

In December and January, states, provinces and the U.S. Fish and Wildlife Service conduct aerial surveys to estimate wintering populations of various geese. For the last two years the mid-continent population of snow geese has been estimated at more than 2 million birds. Since the counts began, 1990 was the first year in which the estimate exceeded 2 million. And that's a lot of geese.

Mike Johnson, migratory game bird management supervisor for the North Dakota Game and Fish Department, likes this comparison: All the Canada goose populations that migrate through the Central Flyway (there are five of them) together come up nearly a million birds short of the mid-continent snow goose population.

But two of those Canada goose populations rarely set foot in North Dakota. The three groups of Canadas that do stop here, though not all at one time, amount to a little more than a half million birds, while Johnson estimates that 80 percent, or roughly 1.6 million snow geese stop in North Dakota each fall. That's probably why 75 percent of North Dakota's goose harvest is snow geese, Johnson said. "They're really the bread and butter of our goose hunting."

For each population of geese, be it snow, Ross, Canada or whitefront, waterfowl managers have written a management plan. Within those plans are population goals for each group of birds.

The population goal for mid-continent snow geese is 1-1.5 million wintering birds. The current population is well above that goal, and has been for many years. While that seems to be good news, the snow goose population may have reached a level that existing habitat, especially breeding habitat, cannot support in the long term.

The Numbers Game

In 1969, there were about 800,000 mid-continent snow geese. Since then, the population trend has been upward. The population almost reached 2 million birds in 1977 (see chart), dropped to 1.4 million in 1985, then topped out at 2.2 million, a record high, in 1990.

"I don't think there's a real clear answer to why they're increasing," Johnson said, adding that it's more likely a number of factors together that have caused the snow goose population to grow.

One of those factors involves the reproductive potential of snow geese. In good years they, as a population, produce lots of young, in bad years they produce few. "We know we've had some bust years," Johnson said of the last decade of reproduction, "but we've also had some really good years."

Another factor may be the significant drop in the number of waterfowl hunters in the Central and Mississippi flyways in the last 15 years. In the Central Flyway in 1977, the snow goose harvest was 306,000 by an estimated 342,000 adult active waterfowl hunters, according to a U.S. Fish and Wildlife Serrvice report. The snow goose population that year was more than 1.9 million.

In 1991, with a mid-continent snow goose population of more than 2 million, the Central Flyway harvest was 209,000. The number of adult hunters had dropped from 342,000 to 177,000. North Dakota active adult hunter numbers dropped from 48,000 in 1977 to 21,000 in 1991. Perhaps not surprisingly, the North Dakota snow goose harvest fell from 124,000 in 1977 to 73,000 in 1991, even though the daily limit was higher.

Other factors, Johnson noted, could include improvements in migration and wintering habitats, adaptation to agricultural practices that provide waste grain as a food source, and perhaps even a shift in preference by goose hunters from snow geese to Canada geese.

Add up all these factors, and you've got a mid-continent snow goose population that is bursting at the seams.

The Nesting Grounds

Snow geese nest in colonies that number in the thousands of birds. Typically, these areas are river deltas and areas along the ocean and coast that have grass, Johnson said, since geese are grazers and depend on vegetation as a food source once they get to their breeding grounds.

Snow geese breeding colonies are spread out all over the arctic. Unlike duck and goose nesting habitat in the prairie pothole region, the remoteness of snow goose nesting habitat has kept it relatively free from impact by man. That remoteness also prevents biologists from getting as much information as they would like on snow goose populations.

Mid-continent snow geese generally arrive at their arctic breeding grounds in mid-May. If the snow is gone, they will begin initiating nests within a few days. If the snow is not gone, they will wait several days. If the snow still is not gone, as was apparently the case this year, they may not nest at all.

"They put on a tremendous amount of fat which they carry north with them to the breeding grounds," Johnson says. "Then they use the energy stored in that fat to produce their eggs, and to incubate their eggs."

Those fat reserves are essential, Johnson says, because even if nesting conditions are perfect when the geese arrive, there is very little for the birds to eat for quite some time. "They rely on that stored body nutrient reserve to lay their eggs and incubate them....If they have to wait too long to initiate their nests, they start burning up their energy reserves and they're not able to nest."

Putting on fat does not seem to be a problem for snow geese.

The fat reserves come largely from waste grains readily found on the northward migration, after the snow melts off the prairies of Nebraska, South Dakota and North Dakota, and eastern Saskatchewan and western Manitoba. In effect, snow geese leap-frog up the Central Flyway following the snow line, until they've built up enough reserves to make the final flight into the nesting ground.

The window of nesting opportunity for snow geese is a short one. There is no time for renesting. "They get one shot at reproduction," Johnson stated. "If it's not there...they have a bust."

Periodic busts on the snow goose nesting grounds are not a major concern to waterfowl managers. Such events have occurred for periodically for centuries, as have years of good reproduction.

What is a major concern is that in recent years, even under good nesting conditions, snow goose productivity is going down. This phenomenon has been documented at the La Perouse Bay colony, Johnson said, and if it exists in other arctic nesting colonies, the signs do not point to a bright future for the mid-continent snow goose population.

 

When More is Not Necessarily Better

The La Perouse Bay colony, on the southwestern side of Hudson Bay, has been the subject of an ongoing study since 1968. Since the study began, the number of breeding pairs has increased substantially, as has the actual size of the breeding area.

In 1968, according to reports by Dr. Fred Cooke of Queen's University in Kingston, Ontario, there were about 1,200 breeding pairs at La Perouse Bay. In 1979, that number grew to more than 4,000. In 1990, the number of breeding pairs was estimated at 7,000.

To fully understand the significance of that increase, we need to go back to snow goose breeding characteristics. Recall that snow geese depend almost entirely on fat reserves to carry them through nest initiation and egg incubation. When the eggs hatch, the adults and goslings eat grass and salt marsh vegetation until they are ready for their flight south.

The growing number of geese at La Perouse Bay has put considerable stress on the vegetation around the colony. To put it more bluntly, "They're destroying the growing vegetation," Johnson said, eating much of the grass down below the soil line.

In the fragile arctic environment, grass does not rebound as fast as it does here on the prairie after a good rain. "Eventually," Johnson predicted, "there won't be enough food there for the goslings to develop, and they simply won't have any reproduction.

"The geese will be able to come up there and nest, but there won't be enough food to carry the goslings into fledging (flight stage), and then you'll have a bust in production," he added. "And you'll have a number of bust years even in good weather years. Eventually the older birds will die out, and you won't have enough young birds to replace them."

In his 1991 La Perouse Bay study report, Dr. Cooke wrote: "...there is good evidence, from several parameters, that production continues to decline within LPB on a per goose basis."

And: "The botanical work of Dr. R.L Jeffries continues to document the disappearance of the salt marsh vegetation which in past years was the major forage of geese. There has also been a decrease in standing crop in the most productive parts of the salt marsh."

And: "Dr. Williams analysis of the long-term data collected during brood rearing has indicated a significant decrease in brood survival over the last 11 years."

Perhaps the most startling revelation of the report is that many LPB snow geese are adapting to deteriorating feeding habitat close to the nesting colony by moving their goslings up to 50 kilometers to alternative brood rearing areas.

Goslings captured in a banding drive close to the nesting colony were in "very poor condition (several hundred grams lighter than in other drives) and immediately started showing signs of stress....Birds that do disperse appear to show better gosling growth and brood survival."

Summarizing the 1991 study year at La Perouse Bay, Cooke wrote: "In recent years the snow goose colony at La Perouse Bay has shown a decline in both adult fecundity (productivity) and gosling survival. Adult survival, on the other hand, has increased, probably because of reduced per goose hunting pressure on the mid-continental population as this population had increased.

"Deterioration in the quality of the traditional feeding areas used for brood rearing, associated with an increase in population size, seems to be the major cause of the poorer growth and survival of young....Whether these demographic changes detected at LPB are specific to the La Perouse Bay colony, or symptomatic of the whole mid-continent snow goose population is a question which must be addressed in the coming years."

Harvesting the Bounty

In his 1991 summary, Dr. Cooke also states that: "Attempts to increase flyway kill might be a way of ameliorating the pressure on the salt marshes."

Increasing the daily limit to 10, and the possession limit to 20, is one way waterfowl managers are trying to increase the harvest. But it may not be as simple as that, as evidenced by the decrease in harvest since the daily limit went from five to seven in 1990.

"The problem with snow geese," Johnson said, "is that they're difficult to hunt....They have adapted real well to survive under the current hunting regulations. They take full advantage of refuges. They take full advantage of half-day hunting. And they take full advantage of their ability to identify decoys spreads and avoid them at all costs."

Like a certain decoy spread in Towner County the day the Halloween storm hit last fall. It's no wonder. Of banded snow geese recovered in North Dakota last fall, a good number were more than 10 years old. One was 20.

One might logically ask, if these older geese are so smart, why did they get shot? It's a numbers game. Since there are a lot of old geese in the mid-continent population, it stands to reason that some will fly into, or over the wrong spot. That still leaves a lot of old birds, though, to spread caution throughout the flock.

Despite their reputation, snow geese can be had. North Dakotans harvest about a third of the snow geese taken in the Central Flyway. The bulk of the harvest occurs in the northern one-third of the state, from Kenmare to Grand Forks.

National wildlife refuges such as Des Lacs, Upper Souris, and J. Clark Salyer are major staging areas, as are numerous waterfowl rest areas and smaller NWRs in the area.

It's no secret that the snow goose migration has gradually shifted west. In 1966, J. Clark Salyer Refuge southwest of Bottineau attracted 80 snow geese. In 1990 the peak fall population was 150,000. In 1980, Upper Souris northwest of Minot had 63,000 snows; in 1991 it had 150,000. In 1980, Des Lacs, the westernmost of the major refuges, had 30,000 geese; in 1991 it had 250,000.


North Dakota Wildlife Sites

Some of that movement is likely a result of the expansion of the snow goose population, Johnson said. More birds are filling up space that wasn't needed before.

In addition, Johnson says waterfowl managers believe snow geese are fairly sensitive to hunting pressure. They may migrate through new areas where hunting pressure is light. Band recoveries and observations indicate that more and more mid-continent snow geese are staging in eastern Saskatchewan and western Manitoba, where there is little hunting pressure, Johnson said.

Agricultural practices also likely played a role in pushing the snow goose migration to the west. Snow geese depend heavily on waste grains for fall food, Johnson said. Fall plowing is more prevalent in the east, he noted, while stubble fields are much more prevalent further west.

While the migration may have shifted, it still comes through the heart of North Dakota. Snow goose hunting opportunities are better than they've ever been, and it wouldn't hurt to put a little more pressure on them, Johnson said. The key is planning a two or three day hunt, scrounging up as many decoys as you can (just about anything white will do), and hoping that among those two or three days, the weather gets nasty. The snow goose population in North Dakota peaks about the third week in October, Johnson noted. Nearly 50 percent of the harvest takes place between October 16 and 31.

Pressed for a recommendation, the state's head waterfowl biologist would watch the weather and plan his trip as late as possible, hoping for a cold, cloudy and windy day. Birds are more inclined to feed under such conditions, he said.



CRAIG BIHRLE is associate editor of North Dakota OUTDOORS.