Standing with your boots in the sand, you look out over the sea as the briny scent of decomposing aquatic vegetation wafts on the breeze. A flock of small, dark geese appears off the coast, flying in a ragged line just above the crashing waves. You could just as easily see these birds on Humboldt Bay, California, as on Long Island, New York, but many waterfowlers wouldn’t recognize them. The geese in question are brant, and while their range spans large portions of the Pacific and Atlantic coasts, many people have never seen them in the wild.
Though technically members of the same species, Pacific and Atlantic brant are found in different flyways and are different enough for scientists to classify them as separate subspecies. The western United States is home to the Pacific brant, commonly known as the black brant. This subspecies gets its common name from the dark brown to black feathers on its chest and belly. Pacific brant breed primarily in coastal Alaska, Arctic Canada, and Russia, with the largest concentration of nesting birds found on the Yukon-Kuskokwim (Y-K) Delta in western Alaska. Brant encountered in eastern North America belong to the Atlantic subspecies, which can be distinguished from Pacific brant by their light brown to white chest and belly. Atlantic brant breed primarily in the Foxe Basin of Arctic Canada on Southampton, Baffin, and Prince Charles Islands. A small population of less than 10,000 brant nest on the Parry Islands in the western high Arctic and share genetics with both subspecies. These birds, which migrate and winter in the Pacific Flyway, have an intermediate appearance and are known as “gray-bellied” brant.
Arctic foxes are a major predator of brant nests throughout the species’ breeding range. Avian predators, including owls and gulls, also pose a threat, as both will eat brant eggs or newly hatched goslings. In recent years, Atlantic brant have faced a new nest predator—polar bears. These large marine mammals have been spending more time on shore in the Foxe Basin due to declining summer sea ice.
Brant rear their broods in coastal salt marshes, where goslings feed primarily on short, nutrient-dense sedges. Vast expanses of these sedges are often referred to as “grazing lawns” due to their closely cropped, dense growth. The combination of short, cold growing seasons and intense grazing by geese has historically maintained the productivity of these important feeding areas. Thus, grazing by goose broods provides an effective positive-feedback cycle that helps maintain highly nutritious food resources for the birds. In the absence of grazing pressure, these habitats can revert to stands of taller, less nutritious plant growth in areas with milder climates, such as the subarctic Y-K Delta. Researchers have documented that this has occurred in some breeding areas, which can adversely affect the growth of goslings.
Once young brant fledge and adults complete their molt, they depart from breeding areas and begin their southward migration. Many other goose species have capitalized on agricultural crops and waste grains, but brant are unique in their reliance on coastal wetlands during the nonbreeding period. Pacific brant feed almost exclusively on eelgrass, which is still abundant in many areas along the Pacific coast. Eelgrass was once the dominant food source for Atlantic brant as well, but this vegetation was devastated by disease during the early 20th century. In response, migrating and wintering Atlantic brant now rely on green algae, saltmarsh sedges, and cultivated grasses on golf courses and athletic fields.
Both brant subspecies fuel their migration by feeding at key staging areas. Izembek Lagoon, near the end of the Alaska Peninsula, is the primary staging area for nearly the entire population of Pacific brant in fall and a significant portion in spring. Expansive eelgrass beds fill the lagoon’s shallow waters at the confluence of the Pacific Ocean and Bering Sea. Warmer winter temperatures have reduced ice cover in the lagoon, which has made eelgrass accessible throughout the year, allowing many brant to spend the winter at Izembek. Only about five percent of the population overwintered on the Alaska Peninsula prior to 1990, but this has increased to nearly 40 percent in recent years.
During migration, Atlantic brant stage along coastal areas of James Bay, a highly productive marine ecosystem at the southern tip of Hudson Bay. Eelgrass meadows in eastern James Bay were once among the most extensive in North America, but more than 40 percent of dense eelgrass beds have been lost since 1995 due to hydroelectric development, changing sea ice patterns, and marine warming. Brant have compensated for the loss of eelgrass by grazing on adjacent uplands, as they have in other portions of their range.
After refueling on fall staging areas, many brant undertake long-distance migrations to their wintering grounds. Pacific brant depart Izembek Lagoon on favorable tailwinds in late fall, flying 2,800 miles nonstop over the Pacific Ocean to coastal lagoons along the Baja Peninsula of Mexico. Some stop on coastal bays and estuaries between Alaska and Mexico (especially on Humboldt Bay in California), with small groups remaining in these areas throughout the winter. Atlantic brant fly over 600 miles overland from James Bay to coastal wintering areas stretching from Long Island, New York, to Cape May, New Jersey.
Despite their extensive distribution, brant are among the least abundant of North America’s geese. The coastal ecosystems that brant rely on throughout their annual cycle are highly sensitive to environmental changes, which can impact brant populations. An estimated 196,000 Pacific brant were surveyed on Izembek Lagoon in fall 2025. Breeding populations of Pacific brant on the Y-K Delta have declined significantly since the 1980s. Researchers attribute this decline primarily to reduced recruitment of young, resulting from nest predation by arctic foxes, large-scale degradation of grazing habitat, and loss of eelgrass beds at important wintering and staging sites along the Pacific coast. In contrast, numbers of nesting Pacific brant on the Arctic Coastal Plain of northern Alaska have increased over time, but these increases have not offset declines on the Y-K Delta. Declines in the three-year average for brant numbers on Izembek Lagoon in fall led to more restrictive harvest regulations for the 2025–26 hunting season.
Recent surveys of Atlantic brant estimated a total population of 133,000 birds. The Atlantic brant population is currently stable but fluctuates from year to year, driven primarily by annual variation in breeding success. In response to multiple years of low productivity, more restrictive Atlantic brant harvest regulations were implemented during the 2023–24 hunting season.
Researchers and wildlife managers remain dedicated to improving our understanding of brant population dynamics, as shown by a recent increase in scientific studies focused on brant across the birds’ range. These efforts and the conservation and management actions that they support will be crucial to maintaining North America’s brant populations for the enjoyment of hunters and other waterfowl enthusiasts in the future.
Jordan Thompson is a PhD candidate in the Department of Fish, Wildlife, and Conservation Biology at Colorado State University. Lindsay Carlson is a PhD candidate in the Department of Biology at the University of Saskatchewan.
