Every spring, Atlantic brant (Branta bernicla hrota), New York Harbor’s smallest goose, is busy getting ready for a demanding breeding season up north. The birds are active nearly all the time eating sea lettuce, preening and getting flight muscles in shape by flying low around the harbor.
The brant’s name comes from the Germanic Old Norse word “brandgas,” meaning “burnt goose,” which refers to its blackish-gray appearance with white feathers underneath and white feathers that resemble a tiny necklace. Brant are different from Canada geese, which are more frequently found around airports and in suburban parks and golf courses. Brant are typically seen foraging for food in estuarine waters or along the shore.
Come May, one by one, the birds begin to gather in large flocks of up to 1,000 or more in Sandy Hook Bay, Raritan Bay, Jamaica Bay, and other nearby brackish areas. Our brant are part of the approximately 181,000 that winter in large flocks along the Atlantic Coast from Massachusetts to North Carolina, according to a 2002 NJ Fish & Wildlife study.
New Jersey Fish & Wildlife also tell us that on average 70% of wintering brant occur in New Jersey, with the south shore of Long Island having the second largest winter population. New York Harbor, nestled right in the middle between New Jersey and New York, is a critical overwintering location for many tired and hungry brant.
By Memorial Day weekend, these bay geese are off for breeding grounds in the high Arctic. It’s a long migration over 700 miles, flying nearly non-stop for several days and at altitudes of several thousand feet above much of northeastern Canada. The birds will nest in chilly coastal tundra of the high Arctic on Baffin Island, Southampton, and on other islands west of northern Hudson Bay.
Brant are monogamous and often return to the same coastal nesting site year after year. They also leave New York Harbor at the same time every year in hopes the Arctic snow has melted. Arriving too early to find nesting grounds completely frozen could be a deadly error, leaving hungry vegetarian birds with few food options.
Predation is also a constant problem in the Arctic. Adult brant must defend their young against persistent attacks from Arctic foxes, and Parasitic jaegers and Glaucous gulls, large avian predators of the chilly north seeking quick and easy meals of baby brant. Incessant attacks regularly mean that female brant must fast or go hungry in order to guard a nest from a raid.
Life is not easy in the high Arctic to raise a family, and the Atlantic brant seem to be on the edge of giving up. Their population is slowly declining.
Over the last several years, wildlife biologists are noticing there are fewer young in the population during winter surveys of Atlantic Brant in the Mid-Atlantic. The lack of young birds suggests something could be going drastically wrong for nesting brant on their Arctic breeding grounds.
But what could it be? Scientists at the University of Delaware have been trying to answer this question for several years. It began in 1979 when Ken Abraham, an adjunct professor at Trent University in Peterborough, Ontario, and a longtime waterfowl biologist first set up a camp in the wet tundra. The first year, 455 brant nests were observed by Abraham, but in 2014 Clark Nissley, a graduate student, and a team of three researchers from the University of Delaware, observed only 44. And of those 44, only two were successful.
Brant aren’t the only ones trying to raise their young in the short northern summer. Research from Clark Nissley and other wildlife scientists suggest that two other geese species could be negatively impacting the brants’ nesting success.
Populations of Snow geese and Cackling geese have rapidly increased in the last 20 years due to the lack of natural predators in some areas of North America and improved food supply from forested land being converted to agriculture. These two species of geese are gradually pushing brant to the margins.
Snow and Cackling geese, both of which arrive to the same nesting sites in the Arctic before brant, often eat existing vegetation, frequently leaving less nutritious plant food available for successful nest initiation, egg laying or individual health for the brant.
Snow and Crackling geese also seem to be actively pushing brant off the best or preferred coastal nesting sites, which in turn lead to a reduction in nest commencement and fledging rates.
The University of Delaware study tells us that when brant are forced to nest farther away from the water in lower quality sites due to competition, they are vulnerable to predators, including Arctic foxes, herring gulls and parasitic jaegers, that prey on their nests during incubation or incubation breaks when adult brant leave their nests to forage. The predators are potentially drawn to the nesting areas because of the influx of Snow and Cackling geese. These predators might normally only affect the brant in low levels, but if high densities of Cackling geese or Snow geese draw these predators in, then the brant may be suffering secondarily as a result of it.
Scientists with the University of Delaware go on to report that foxes were the largest threat to the brant, taking a number of eggs from nests. Using time-lapse and motion-sensing cameras, the crew found that out of the 42 failed brant nests, they were able to pinpoint what caused the failure for 28 of the nests, and 23 of those nests failed due to fox predation.
In addition, many bird species that nest in the same areas as the geese show signs of decline or have otherwise been affected, including semi-palmated sandpipers, dowitchers, long-tailed ducks, red-breasted mergansers, Lapland longspurs, among others.
For the brant, declining populations is sadly nothing new. In the early 1930's, brant went into a severe population decline when a disease wiped out nearly all of the Atlantic Coast's eelgrass, which up to that time had made up about 80 percent of the birds' diet.
Fortunately for the brant, the birds slowly rebounded by turning to other food sources for their survival. Brant switched to sea lettuce and other marine algae, which had always been part of their diet, but in small quantities. Eventually the eelgrass recovered and the brant population recovered as well.
But then life took another turn for the worse. A serve cold snap in the early 1970s caused the population to decline dramatically. Ice and snow covered breeding sites into late July. This resulted in almost total nest failure for several years.
The total population of brant, which, was estimated at 200,000 in the late 1960s, dropped to 73,000 early in 1972, and was estimated to be only about 40,000 in 1973. Surveys in 1971 revealed that only 7 per cent of the wintering population of brant was made up of young birds. This figure dropped to less than one percent the following year, indicating almost no nesting success.
It’s data that seems to be remarkably similarly to current findings. An April 28, 2016 edition of Science Daily reports that while brant did have a better nesting success in 2015 than in 2014, this was still not likely enough to rebound the low population. Their nest success was only 17 percent in 2015 compared to 6 percent in 2014.
Down around New York Harbor, there are threats as well to the small bay goose from coastal development, water pollution, especially from trash and garbage, and from oil and chemical spills. Atlantic brant are also hunted for sport in both New York and New Jersey, though under strict regulations.
Will brant be able to come back once again and make a recovery as they have in the past? It will be interesting to see what the future holds for the Atlantic brant, a blackish-gray goose that winters in New York Harbor and spends summers in the North Pole.