Bird Photos
Species Accounts
Conservation Issues
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Migrating Geese
The fantastic annual migrations that birds make between their breeding
and wintering grounds is one of the wonders of our natural world. Most of
the world’s 29 or so species of geese are no strangers to migration, and
some routinely accomplish amazing feats. In Asia, Bar-headed Geese (Anser
indicus) regularly migrate over the Himalayan Mountains, even over Mt.
Everest at an altitude of 30,750 feet (9375 m) where the air is thin and the
temperatures drop to minus 60 degrees F.
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Migrating birds, especially
waterfowl, follow broad but well defined migration routes called flyways or
migration corridors. There are four primary corridors in North America. From
east to west, they are the Atlantic, Mississippi, Central and Pacific
flyways.
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Figure 1 - Migratory Flyways
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Figure 2 - Migratory Flyways
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Many species of geese and other
waterfowl breed in the far northern reaches of North America, and begin
their journey south following well defined geographical features like
coastlines, rivers and mountain ranges.
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Snow Geese breed in the Arctic
Tundra and winter in farmlands, lakes and coastal areas in the American
south, southwest and east coast. These attractive geese occur only in North
America, and make an annual round trip journey of more than 5,000 miles at
speeds of 50 mph or more. Seen in flight, adults are white with jet black
wing tips.
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Figure 3 - Snow Geese (Anser caerulescens) |
Figure 4 - Snow Geese (Anser caerulescens) |
In winter months, Snow Geese
form highly gregarious flocks that may number into the thousands. The bill
of the Snow Goose has a distinctive “grin patch” along its side. The Ross’s
Goose looks like a Snow Goose, but is smaller, and its bill lacks the “grin
patch.” The two grayish birds shown here are young Snow Geese.
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The dark bird shown here near
the center of the photo is a blue phase of the Snow Goose. Note the white
face, and the very dark body. Formerly considered a separate species, the
blue phase and the white phase of the Snow Goose are now lumped into one
species. The similar but smaller Ross’s Goose looks very much like the Snow
Goose, and also has a blue phase that is considered rare.
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Figure 5 - Blue Phase of the Snow Goose
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Figure 6 - Snow Geese in Flight
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Snow Geese winter in immense
flocks, sometimes numbering in the tens of thousands. When they take flight,
the flock appears as a white cloud rising from the marsh. Population
biologists census waterfowl in winter months to determine population trends.
Can you estimate the number of geese visible in this flock?
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The Brant is the salt water
cousin of the Canada Goose. These birds breed farther north than any other
species of goose, and winter in coastal areas of Europe, North America and
Japan. Note the white patch on either side of the neck. These birds are
truly marine. They have special salt excreting glands that enable them to
drink salt water and feed on eel grass, crustaceans, mollusks, and marine
worms.
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Figure 7 - Brant (Branta bernicula)
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Figure 8 - Brant in Flight
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Brant in flight have a dark
appearance with a conspicuous bright white rear end. Flocks in flight do not
form up into a “V” formation, but instead fly low over the sea in long wavy
lines that seem to ball up then string out again with no particular leader.
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The Canada Goose is widespread
over North America, and has been introduced to Europe and New Zealand. The
white patch on its face and throat is distinctive. Some 10 races are
recognized, ranging from the very large nominate race to the darkest and
smallest race B. diminuta. These geese are migratory, but in many
residential areas with plenty of food, water and shelter, they are becoming
quite resident. Some local populations are getting so large that they are
becoming a pest species.
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Figure 9 - Canada Goose (Branta canadensis)
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Figure 10 - Canada Goose with neck band
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Neck bands or collars are
useful to quickly locate and identify individual geese in a flock. If you
should see a neck band on a goose, take note of its number, its color, and
the color of its numbers. You can report the location of the band encounter
by calling the Bird Banding Laboratory toll free number at 1 800-327-BAND.
Your report will help gain information on the bird, and you will receive a
nice certificate for your efforts.
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Interesting Facts About Geese
Geese and some other species of birds migrate in distinctive
“V” or “U” formations or in lines. By taking advantage of the wing tip
vortex of the bird in front, each bird can save energy by reducing drag. The
energy savings in flight can be as much as 50%.
Two Snow Geese feeding within a few feet of each other in
November 2002 near Bombay Hook Delaware had yellow neck bands that were
placed on the geese in 1999 in a colony on the southwestern part of Bylot
Island, Northwest Territories (73.13N, 78.34W).
The distance between the banding location and the encounter
location in Delaware is about 2,500 miles. Both the east end of Bylot Island
and the sighting location in Delaware are almost right on the 76th longitude
line.
Encounters such as there demonstrate that families of geese
do not break up after the breeding season, but form strong family units that
migrate and winter together until they return to their breeding ground. Only
then do the yearlings leave to start their own families. Indeed, some geese
mate for life. Canada geese can live up to 30 years in the wild and longer
in captivity.
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