The Brant goose (Branta bernicla) is a distinctive species within the waterfowl family. These small, dark geese are adapted to coastal environments, strongly associating with marine habitats throughout much of their annual cycle. Understanding the Brant involves exploring its unique physical traits, coastal living spaces, specialized diet, and social behaviors.
Recognizing a Brant Goose
Identifying a Brant goose involves observing its compact size and characteristic plumage. This small goose measures between 22 to 26 inches (55-66 cm) in length, with a wingspan ranging from 42 to 48 inches (106-121 cm), and weighs about 1.9 to 4.9 pounds (0.88-2.2 kg). Its head and neck are black, featuring a small white patch on either side of the neck that can appear as a partial or near-complete collar, varying slightly among subspecies.
Body plumage varies by subspecies but generally appears dark grey-brown. The Pacific subspecies (Black Brant) has a darker, sooty-brown back and belly, often with a prominent white flank patch. The Atlantic subspecies may have a paler, light grey belly. Its under-tail is white, contrasting with a short, black tail—the shortest among all goose species. The Brant has a short, stubby black bill, and its legs and feet are also black. In flight, their wings appear long, and their wingbeats are rapid compared to other geese, with a broad white edging on black tail feathers creating a characteristic “V” shape.
Where Brant Geese Live
Brant geese exhibit a circumpolar distribution, breeding in the high Arctic tundra and wintering along temperate-zone sea-coasts. Their breeding grounds are found on low-lying wet coastal tundra, including areas in Arctic Canada, Alaska, Siberia, and Greenland. They often nest in loosely aggregated colonies near small ponds or elevated locations, providing some protection.
During migration, these geese undertake long-distance journeys from their Arctic nesting grounds to warmer coastal areas. Pacific Brant primarily winter along the west coast of North America, from British Columbia to Baja California, Mexico, often staging at locations like Izembek Lagoon in Alaska. Atlantic Brant winter along the Atlantic coast of the U.S., from Massachusetts to North Carolina, with some populations wintering in Western Europe. Their winter habitats are primarily coastal, favoring tidal estuaries, salt marshes, bays, and lagoons abundant with seagrasses. They rarely venture far from saltwater environments, though some populations have adapted to foraging on agricultural land a short distance inland.
What Brant Geese Eat
The diet of Brant geese is primarily vegetarian, with a preference for aquatic plants found in their coastal habitats. Their primary food source is eelgrass (Zostera marina), which they graze in intertidal zones during migration and winter. They forage by wading or tipping up in shallow water, or by walking on tidal flats when the tide exposes their food sources.
When eelgrass is less available, Brant adapt their diet to include other marine vegetation such as sea lettuce (Ulva) and various green algae. The decline of eelgrass beds in the 1930s forced some populations to broaden their diet. On their Arctic breeding grounds, their diet shifts to include sedges, grasses, and pondweed, along with some aquatic insects, mollusks, and worms. In recent decades, some Atlantic Brant populations have also started feeding on turf grasses in upland areas, including golf courses and parks, as an adaptation to changes in their traditional food supply.
Life and Habits of Brant Geese
Brant geese are social birds, seen in large flocks outside of the breeding season. They maintain strong social bonds and form monogamous pairs that last for life. Mated pairs travel together to their breeding grounds, and family units remain cohesive within larger flocks, even during migration and winter.
Their vocalizations are distinct, characterized by a low, guttural “crrr-oonkkk” call, which helps them maintain cohesion within flocks, especially during flight. They also produce a sharper “cruk” alarm call to warn others of potential threats. Brant exhibit hierarchical social structures within their flocks, where pairs with young dominate those without, and unpaired birds are at the lowest level. Daily activities revolve around foraging, and they roost in groups at night, favoring sheltered bays and coastal waters. While their population numbers are considered stable, they are subject to challenges such as habitat loss and the availability of their food sources.