What are “light geese,” and why is there a special control period?
There are several distinct species of geese in North America. Several groups have become overabundant, specifically greater and lesser snow geese and Ross' geese that nest in Arctic and sub-Arctic regions of Canada and migrate and winter throughout the United States. Ross' geese are commonly mistaken for lesser snow geese due to their similar appearance. However, Ross' geese are smaller and have a shorter bill. Ross' geese mix extensively with lesser snow geese on the breeding and wintering grounds and on stopover areas along migration corridors. Both Ross' geese and lesser snow geese nest in colonies along the Hudson Bay Lowlands, which are experiencing severe habitat degradation. Scientists and managers from across North America agree that some populations of light geese have become so numerous that their Arctic and sub-Arctic nesting habitats cannot support them. Light geese are literally eating themselves out of house and home.
Surveys show that the breeding population of mid-continent light geese exceeds 5 million birds, which is an increase of more than 300 percent since the mid-1970s. The population has increased more than 5 percent per year for the past 10 years. And, although efforts have been made to control goose populations in the past, those efforts have not been adequate.
The unprecedented numbers are not only a problem for the light geese themselves but also for other wildlife and plants that share their habitats. At these high population levels, parts of the fragile tundra habitats where light geese traditionally nest are being seriously degraded and/or destroyed. Because snow geese and Ross' geese are colonial birds, they do everything in large groups. When groups arrive in an area to feed, they remove an immense amount of plant material simply because of their large numbers. On the breeding grounds, snow geese use a feeding behavior called "grubbing," in which they probe their bills below the ground surface and actually turn the soil over in search of high-energy roots and tubers. Snow geese are also causing damage to crops in farm fields on their wintering grounds.
Is the increase in population numbers affecting light geese?
Yes, snow geese in the mid-continent region are showing signs of overpopulation through lower-than-normal body size in both juveniles and adults. There also has been an increase in parasites and a decrease in gosling survival.
Are light goose numbers affecting other species?
Yes, there are indications that goose overabundance is already impacting other sub- Arctic and Arctic wildlife. Initial studies suggest that some species of nesting birds in the areas where severe damage has occurred have experienced direct loss of nesting habitat, and the drastic declines in native plant communities have likely caused significant changes in the food base as well. There are indications that a number of bird species that nest in the same areas as the geese are declining, including the semi-palmated sandpiper, red-necked phalarope, dowitchers, Hudsonian godwit, whimbrel, stilt sandpiper, yellow rail, American wigeon, northern shoveler, oldsquaw, red-breasted merganser, parasitic jaeger, and Lapland longspur, among others.
Why are light goose numbers so high?
Scientists believe there are five primary factors that together have led to the unprecedented populations. The primary factors are:
So, how can we control light geese and get them more in sync with the available habitat?
- An increase in food available to the birds as they migrate and as they spend the winter allows higher survival and reproduction.
- An extensive network of state, provincial, Federal, and private wildlife refuges has been established for the primary purpose of conserving migratory waterfowl populations.
- Harvest rates for snow geese have not kept pace with population growth in past years. The birds tend to be difficult to hunt, which leads many hunters to pursue other types of waterfowl instead.
- Climate factors also helped snow geese and Ross' geese (a warming trend in some nesting areas during the late 1960s and 1970s allowed higher-than-normal reproduction);
- Decreased adult mortality means birds are living longer, the average adult lives 8 years and some may live to be 20.
Unfortunately, light geese aren’t easily controlled by natural predators. In the arctic, predators are not numerous. Some light geese are taken by coyotes and red fox on their migration and wintering grounds, but the numbers are not significant.
From a biological perspective, the key to reducing the population of light geese is to reduce the survival rate of adult birds. Hunting has traditionally been used as an effective tool to manage migratory game bird populations. Although there are other options available, without nationally regulated hunting, resource management agencies will have to spend significant amounts of money to control the populations directly on their breeding or wintering grounds. Such alternatives could also potentially result in massive waste of goose carcasses that otherwise would be consumed by hunters or donated to food banks.
The US Fish and Wildlife Service is responsible for setting seasons and bag limits for migratory birds in the United States. During the past 20 years, the USFWS has addressed the problem in several ways. In 1980 the length of the migratory bird hunting season was increased to 107 days- the maximum allowed by the Migratory Bird Treaty Act. During the next two decades, daily bag limits (number of geese a hunter can take in a single day of hunting) were increased to levels beyond those allowed for any other waterfowl species, and possession limits (number of geese a hunter may have in his/her possession) have been removed. We now have the special hunting season with extended hours and the use of electronic calls allowed.
Will these efforts reduce the numbers of light geese to the required level?
Only time will tell. This is a complex issue and one that has far reaching consequences for light geese and those plants and animals with which they share the arctic ecosystem. For additional information on the snow goose issue go to: http://www.fws.gov/migratorybirds/CurrentBirdIssues/Management/snowgse/tblcont.html.