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Blackwater National Wildlife Refuge
2145 Key Wallace Drive
Cambridge, MD 21613
410-228-2677 TDD/800-735-2258 |
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The advance guard arrives in late September, and numbers
steadily increase throughout October until the current peak concentration of 35,000 is
reached in early November. About 25,000 geese remain at Blackwater all winter,
while others use the Refuge as a resting and feeding area on their way
farther south.
Although it is hard to imagine the Refuge without Canada geese, between 1933 and 1938 none wintered on Blackwater. Goose concentrations on the Delmarva Peninsula began increasing in the 1940s due to an increased food supply resulting from the widespread adoption of the mechanized corn picker that "wasted" much more grain than was left in the fields when corn was harvested by hand. From a maximum of 5,000 geese in 1942, the populations increased at Blackwater until they peaked at 105,000 in 1963. Due to the significant loss of wetlands and thousands of acres of three-square bulrush marshes, drought conditions, reduction in the Refuge's cropland acreage, severely depressed reproductive success on the breeding grounds, and increased hunting pressure on the Eastern shore, the Canada goose population declined to approximately 20,000 by 1992. Recent improvements in management practices, however, are helping to restore numbers to the objective level of 50,000.
In conjunction with the North American Waterfowl Management Plan, Blackwater NWR is directing its management effort towards maintaining and improving habitat to help restore diminishing waterfowl populations. Over 12,000 acres of natural brackish marsh and open water provide resting and feeding areas for migratory waterfowl. The primary plant species in these areas highly valued for food for Canada geese is the Olney three-square bulrush.
Since 1992, more than 460 acres of croplands have been managed annually to provide a diversity of food sources high in carbohydrates for energy and in proteins for molting, juvenile body growth, and to help waterfowl return to the breeding grounds with sufficient reserves for reproduction. Refuge-planted crops high in fat-building carbohydrates include millet, soybeans, sorghum (or milo), corn, and buckwheat; also several types of clover, winter rye grass, and winter wheat provide excellent sources of green browse.
Natural vegetation is also provided as a food source through a program called "moist soil management." Water is gradually removed from approximately 300 acres of freshwater impoundments in the spring to provide a wet seed bed for germination of natural vegetation. The plants also harbor higher insect populations which, when flooded in the fall, provide important protein sources for feeding waterfowl.
Geese feed on tender shoots and roots of aquatic plants in
the marshes and on grain and "green browse" in the fields. An adult goose needs
an average of one-half pound of food a day -- less in warm weather and
more during cold periods and prior to long distance flights.
In extreme cold and wind, geese will sit out the weather and not eat. They save energy by not flying. While waiting, they tuck their feet and bills into their soft down feathers. Extremities which are not covered with insulation lose heat rapidly and deplete energy reserves needed for migration, nesting, and molting in the spring.
When daytime hunting pressures in the area surrounding Blackwater are heavy, the geese often resort to feeding at night when the moon is full, returning to the refuge and its marshes during the day. This explains why there are days when there appear to be no geese here; during these periods, sizable goose flocks are usually only seen at dawn and dusk.
The color patterns of a Canada goose are so distinctive that it is almost impossible to confuse it with any other species. The head, bill, neck, feet, and tail are black, while the cheek patches, which meet under the white chin, are its most easily recognized characteristic. The upper parts are grayish-brown, with the underparts lighter and becoming white near the tail.
It is not easy to distinguish a gander (male) from a goose (female). Generally the gander is acknowledged as the larger of the pair, and he has a deeper sounding call.
At Blackwater, the average Canada goose weighs about 8 pounds, but their weights may range from a small 6 pounds to over 15 pounds for an older bird. The wingspread varies from 5 to 6 feet.
Canada geese held in captivity often live 20-40 years, but the geese who migrate to Blackwater probably live an average of 5 to 10 years.
Geese form very strong, lasting social bonds. A pair usually mates for life, although when one dies, the other remates. Some Canada geese nest for the first time at the end of their third year. They usually lay 5-8 eggs requiring about 28 days of incubation. The proud parents are very protective of their young goslings. Family ties remain strong throughout the first year.
While most Canada geese go north to nest, some resident geese remain at Blackwater where the young broods may be seen in early summer. This flock of resident Canada geese began with injured adults who could not migrate and stayed to raise their families at Blackwater. However, the resident geese have multiplied and become pests that often destroy crops planted for the migratory waterfowl.
There has been much speculation as to what causes the geese
to begin their spring and fall migrations. The increasing or decreasing length
of days, combined with weather conditions and other variables, motivate
the geese to migrate twice yearly. Fat deposits accumulate just prior
to migration and provide energy for the long flight.
The usual "V" formation provides each goose (except the leader) with favorable air currents in which to fly. Older geese alternately share the lead position. Geese have been observed at altitudes of 29,000 feet, although the normal migration altitude is only 3,000 feet.
Most of the Canada geese wintering at Blackwater NWR and other areas of the Eastern Shore travel north in the spring. The flocks begin moving out in late February and most are gone by mid-March. From here they travel to their ancestral nesting grounds on the Ungava Peninsula near James Bay, Canada. There, during the summer months, they nest and rear the young -- only to begin the cycle once again with their return to southern wintering grounds in the autumn.