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Atlantic Brant Migration and Breeding Ecology Study 2021

Atlantic Brant Migration and Breeding Ecology Study 2021

January 21, 2021

2020 Spring Migration
2020 Full Annual Cycle Migration

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The NJDEP Division of Fish and Wildlife is participating in a multi-year Atlantic brant migration and breeding ecology studies collaborating with the New York Department of Environmental ConservationCanadian Wildlife Service, and University of Missouri, School of Natural Resources.

Atlantic brant are a small goose species that breeds in arctic Canada and winters in the Mid-Atlantic region of the United States. About 90% of the entire population winters along the coast of New Jersey and New York.

During the past three years, nearly 2,500 brant have been tagged with three different types of auxiliary markers in addition to “standard” metal leg bands. Please note that all brant with auxiliary markers will also have a standard metal band. Help from the public reporting these encounters is critical to the success of this project. You may encounter these four types of markers:

1. Backpack transmitters. Some birds carry these units (Figure 1). Note that many, but not all, brant with backpack transmitters may also be wearing colored leg bands.

2. Colored leg band with geolocator. The geolocators are clear, plastic electronics devices about the size of a “fat nickel” and are attached to a red and white plastic leg band with a plastic cable lock tie (Figure 2). Geolocators gather light data, have a 5-year life, and reveal two important pieces of brant ecology. First, geolocators are only put on females, and “signatures” in the data reveal whether a given female attempted (or not) to breed in a given year. Second, geolocators also provide coarse location data through the full annual cycle.

If you shoot or find a dead brant with a backpack transmitter or geolocator: Please contact Ted Nichols at 609-628-3218 or by e-mail to return the device(s). If undamaged, transmitters can be reused on future study birds. Unlike a transmitter, geolocators do not transmit a signal or beacon but rather store their data internally. In order to obtain any previous location data from a geolocator, we need to get the device in hand and download the data to a computer. To facilitate retrieving the geolocator, the Division will send hunters a self-addressed, stamped, padded envelope to return the device. Hunters who want to retain a geolocator or transmitter as a “keepsake” will be given the unit back or provided with a “dummy” unit.

If you see a live brant with a red and white band and geolocator: These bands are red with white and have 3 codes; the first code is a letter, followed by 2 numbers. Please report these observations to US Bird Banding Lab at REPORTBAND.GOV.

3. Colored plastic leg bands. Nearly 1,700 brant have been marked with various colored bands with black, white, or yellow letters and numbers with only one letter or number on each band (Figure 3). Bands have many different colors. These birds have one band on each leg. Bands on each leg may be the same or different colors.

If you shoot or find a dead brant with a colored marker, please report it to the US Bird Banding Lab at REPORTBAND.GOV.

If you see a live brant with a colored leg band: Note that there is one band on each leg and it is critical in the report that you differentiate which marker color and code is on which leg (right or left). Please report these observations to US Bird Banding Lab at REPORTBAND.GOV.

4. “Standard” metal leg band. Brant with “standard” metal leg bands that are shot or found dead should be reported to US Bird Banding Lab at REPORTBAND.GOV. On the rare occasion that these codes can be read on live birds, they can also be reported to the Lab.

Band “Targeting” by Waterfowl Hunters

A very small proportion of waterfowl are marked with bands in North America. As such, standard leg bands and especially auxiliary markers (for example, tarsal banded brant) are often viewed as “trophies” by waterfowl hunters and are sometimes sought as unique “targets” rather than just harvesting the first birds that come into the decoys in a given day. Although the bands used in this study are generally small and difficult to see in a hunting situation, hunters are urged to not specifically “target” Atlantic brant marked in this study.

For a better understanding of the band “targeting” issue, and how it can affect waterfowl management, please check out Episode 34 – Band Reporting and Band Targeting, by Dr. Mark Lindberg at the University of Alaska on Ducks Unlimited web site:

Atlantic brant with GPS backpack transmitter
Figure 1. Atlantic brant with GPS backpack transmitter.
Figure 2. Atlantic brant with tarsal band and geolocator.
 Brant with colored plastic leg band
Figure 3. Atlantic brant with colored plastic leg band.

Study Objectives

These studies are deploying these various markers on both the wintering grounds in New Jersey and New York as well as the breeding grounds in Nunavut, Canada. Marked birds will provide insight into the following Atlantic brant research questions:

  • How faithful are brant to wintering areas within and among years?
  • What is the breeding propensity of Atlantic brant?
  • How does annual breeding propensity vary with annual arctic summer weather conditions?
  • What is the age at first breeding for Atlantic brant?
  • Compare breeding propensity estimates from geolocators with recruitment estimates from color-banded birds with young to develop a more complete measure of annual productivity.
  • How faithful are brant to breeding areas among years?
  • Do brant molting at the locations currently marked during the summer period use the same wintering and/or migration areas? Do they have the same migration timing?
  • Are the current Atlantic brant preseason (summer) banding stations adequately or reasonably reflect the wintering distribution of brant?
  • What are the key staging areas used during spring and fall migration and is there annual variation in these stopover sites?
  • Is there a relationship between spring phenology, timing of nesting, and timing and rates of movement?
  • During winter, are brant distributed in the same areas as the Mid-Winter Waterfowl Survey? If so, the survey is representative of the wintering population; if not, adjustments to the geographic coverage of the MWS need to be made.

We appreciate the cooperation and interest from the public.

Atlantic brant were captured for marking on the wintering grounds in New Jersey and New York by luring them to rocket nets using decoys.
Click to enlarge

Molting, flightless Atlantic brant were also captured on their arctic breeding grounds during August in Baffin Island (pictured), Nunavut, Canada. Note study birds with transmitters and tarsal bands with geolocators to far right and in center of photo. Atlantic brant goslings in foreground.
Click to enlarge

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Last Update: April 10th, 2023