Ecology of the Atlantic Brant

Atlantic brant (Latin scientific name: Branta bernicla hrota) are a member of the goose family. Brant typically weighing 3 lbs. or less, much smaller than their close cousins the Canada goose (Branta canadensis). The distinctive white cheek patch found on the Canada goose is replaced on the brant by small white bars forming a ring around the neck. In flight, the brant has a very fast wing beat similar to ducks.

Atlantic brant mate for life unless one mate is lost, and begin breeding around 3 years of age. Brant migrate to the arctic circle and beyond to breed. Major breeding colonies are located in the Foxe Basin west of Baffin Island. This study may identify previously unknown breeding colonies. On the breeding grounds snow melts in mid-June, and winter returns in early September. In an average year this leaves just enough time to lay a clutch of eggs, incubate them and raise goslings to flight stage. In years when snow melt is late female brant reabsorb eggs to retain nutrients that would otherwise be lost in an unsuccessful breeding attempt. This process is known as atresia.

Little food is available when brant arrive on the breeding grounds. In fact, female brant utilize nutrients stored in body fat to produce eggs and to sustain them during incubation. They obtain these nutrients while feeding at migration stop-over sites. This study will document the location of stop over areas that are critical to brant reproduction and survival. James Bay is believed to be one of the most important spring staging areas for brant. Little is known about staging areas in the United States

Brant nest in low areas along the arctic coastline. Females lay 4 to 6 eggs in a bowl shaped depression lined with down. Eggs hatch after 24 days of incubation. Once the eggs hatch, the male assumes the leading role in herding the brood, with the female following close behind. Young brant feed on marine invertebrates, mosquito larvae, and various plants. As the brant age their diet shifts to one of almost all plant matter consisting of sea lettuce, eelgrass, and widgeon grass.

Atlantic Brant Telemetry Study

1. Clarify migration routes and the timing of migration,
2. Identify staging areas used by brant during migration,
3. Clarify boundaries of the breeding range,
4. Search for previously unknown breeding colonies.

Most radioed brant receive a VHF transmitter weighing approximately 33g (1.16oz.). Each VHF transmitter emits a unique signal at a specific frequency. Biologists, use a special receiver and antenna to monitor radioed brant. The signal can be heard up to 2 miles away on the the ground, and up to 5 miles away when using aircraft. When a signal is heard the location of the brant is recorded on a map.

Some of the brant receive a satellite transmitter, which weighs approximately 30g (1.06oz.). The satellite transmitters send their signal to satellites orbiting the earth. These transmitters are programmed to turn on several times a week. The satellite calculates the position of the transmitter. This information is then downloaded from the satellite to a computer, where they are plotted on maps.

Both types of transmitters are attached around the body using a soft cloth harness that is similar to a backpack carried by children. The transmitters are designed so that they do not interfere with the birds daily activities such as swimming or flying. The weight of the transmitter is less than 3% of the birds total body weight.