By Dale D. Humburg
When I was growing up, I left my bedroom window open in the fall so I could hear geese migrating during the night. Naturally, I had several questions. What kind of geese were they? Where were they coming from? How many were there?
I now know that most of the birds I heard in the night sky were lesser snow geese. They are among seven species and 17 subspecies that the Arctic Goose Joint Venture considers when developing research and monitoring priorities as part of the North American Waterfowl Management Plan. Included are emperor geese; Ross’s geese; two subspecies each of greater white-fronted geese, brant, and snow geese; five subspecies of Canada geese; and four subspecies of cackling geese.
While collectively known as “Arctic geese,” these birds do not nest exclusively above 66.5 north latitude, which is commonly known as the Arctic Circle. Their breeding range is more appropriately defined as the tundra north of the tree line spanning approximately 3,000 miles across Alaska and northern Canada. Many important breeding areas are located below the Arctic Circle, around Hudson Bay, Labrador, and the Alaskan coast, and most northern-nesting Canada geese actually breed in the subarctic.
While Arctic geese are identified by species, they are managed as separate populations—24 in all. Delineation by population is more relevant to waterfowl managers because population-specific harvest regulations, habitat protection, and surveys can be focused on geese that use specific breeding grounds, migration routes, and wintering areas.
My first goose survey on the western shores of Hudson Bay was a real eye-opener. The region was remote, incredibly diverse, and relatively untouched. Return trips over 25 years along with banding and survey work above the Arctic Circle added to my appreciation for the vast distance between the birds’ wintering areas and breeding grounds, the brief window of opportunity they have to reproduce, and the considerable variation in nesting conditions that occur from year to year.
Migration is costly for northern-nesting geese. In flight, waterfowl expend 13 times more energy than they do at rest. Consequently, the 2,000-mile trip that greater snow geese make from the New Jersey coast to Canada’s Bylot Island takes quite a few calories. The same holds true for cackling geese traveling from the Texas Panhandle to Cape Dominion on Baffin Island or Ross’s geese en route from Bosque del Apache National Wildlife Refuge in New Mexico to Karrak Lake in the Queen Maud Gulf.
Trials of the Tundra
Across the northern breeding grounds, nesting opportunities for geese are dictated by the timing of snowmelt, which in some years can be delayed until mid-June. In an early spring, egg laying ensues soon after the birds return, but if breeding geese are delayed by unfavorable weather, females must draw upon stored fat reserves to sustain themselves. During the incubation period, females lose the majority of their fat stores and their body mass can decline by half. In a late spring, when nest initiation is delayed, some geese don’t survive the incubation period, while others may not nest that year.
Reduced productivity is the direct result of nesting delays, and in some especially late springs, the outcome can be a complete nesting failure for geese in that location. In light of the Arctic’s compressed summer season, completing the production cycle within 10 to 12 weeks is quite a biological feat. At least the long summer days offer extended opportunities for goslings and adults to feed, molt, and regain flight.
In just three months, snow and freezing conditions typically return to the northern nesting grounds, so geese must be ready by summer’s end to make the long migration to their wintering areas far to the south. The all-stars of the fall migration are Pacific brant, which fly 2,000 miles nonstop over the Pacific Ocean from staging areas on the Alaskan Peninsula to Northern California. From there, they fly another 1,000 miles to their wintering grounds in Baja California.
Challenges of Management and Monitoring
Just a few decades ago, management of most northern-nesting goose populations focused on increasing the birds’ numbers and regulating harvest on a few key migration and wintering areas. In recent years, however, most goose populations have increased dramatically. Estimates derived from band recoveries and harvest data now indicate that North America is home to at least 2 million Ross’s geese, 13 million midcontinent lesser snow geese, 4 million cackling geese, and 2.5 million greater white-fronted geese.
As goose numbers have increased, more liberal regulations have replaced short seasons, conservative bag limits, and harvest quotas for most goose populations. The result has been a twofold or greater increase in harvests of white-cheeked geese (Canada and cackling geese), greater white-fronted geese, and light geese (Ross’s and snow geese). Increased harvests of the latter have largely occurred as a result of liberalized hunting regulations allowed under a conservation order for light geese.
The importance of research and monitoring is obvious in the case of light goose conservation and management. Although harvest has more than doubled under the conservation order, populations have at best only stabilized at high levels. Closely monitoring population size and production is even more essential when harvest has been relatively ineffective in reducing numbers. Continuing to monitor impacts on other Arctic regions and monitoring recovery of tundra habitats already impacted by overabundant geese are ongoing priorities.
Harvest management continues to be an important tool but has become more challenging as some populations have increased while others remain at relatively low levels. For example, allowing increased harvests of abundant populations of Canada geese and white-fronted geese becomes particularly difficult when small populations of dusky Canada geese, Aleutian cackling geese, or tule white-fronted geese share the same migration and wintering areas. Research and monitoring are particularly important for species with lower reproductive potential, limited distribution, or specialized habitat requirements. Emperor geese and brant, for example, rely on estuarine habitats and associated eelgrass as their primary food source. Rising sea levels that threaten eelgrass beds and increase feeding depths are long-term conservation issues facing these species.
Detailed research on Arctic geese has a long history. Decades ago, biologists had the foresight to establish research camps dedicated to investigating goose breeding ecology and habitat changes. These efforts will continue to be essential for tracking the status of populations, improving surveys and banding, monitoring less abundant populations, tracking light goose impacts on Arctic habitats, and projecting impacts of a changing climate on goose habitat.
I remember the first goose I shot—a snow goose I took from a small flock over a couple of dozen floating decoys. At the time, peak snow goose migration in north Iowa was in mid-October and giant Canada geese had yet to be reintroduced to the area. Just hearing geese was something special. To me, even with today’s abundant goose populations and management challenges, it still is.
Before his retirement, Dale Humburg served as chief scientist and senior science advisor for Ducks Unlimited.