Canada Goose (Branta canadensis)
The Canada Goose
(Branta canadensis) is a wild goose belonging to the
genus Branta, which is native to Arctic and temperate regions of North
America, having a black head and neck, white patches on the face, and
a brownish-gray body. It is quite often called the Canadian Goose, but
that name is not strictly correct, according to the American
Ornithologists' Union.[2]
According to the Oxford English Dictionary, the first citation for the
'Canada Goose' dates back to 1772.
Taxonomy
The Canada Goose was one of the many species described by Linnaeus in
his 18th-century work Systema Naturae.[3] It belongs to the Branta
genus of geese, which contains species with largely black plumage,
distinguishing them from the grey species of the Anser genus. The
specific epithet canadensis is a New Latin word meaning "of Canada".
A recent proposed revision by Harold Hanson suggests splitting Canada
Goose into six species and 200 subspecies. The radical nature of this
proposal has provoked surprise in some quarters, such as Rochard Banks
of the AOU, who urges caution before any of Hanson's proposals are
accepted.[4]
Description
Yellow plumage of goslingThe black head and neck with white
"chinstrap" distinguish the Canada Goose from all other goose species,
with the exception of the Barnacle Goose, but the latter has a black
breast, and also grey, rather than brownish, body plumage.[5] There
are seven subspecies of this bird, of varying sizes and plumage
details, but all are recognizable as Canada Geese. Some of the smaller
races can be hard to distinguish from the newly-separated Cackling
Goose.
This species is 76-110 cm (30-43 in) long with a 127-180 cm (50-71 in)
wingspan.[6] The male usually weighs 3.2–6.5 kg, (7–14 pounds), and
can be very aggressive in defending territory. The female looks
virtually identical but is slightly lighter at 2.5–5.5 kg (5.5–12
pounds), generally 10% smaller than its male counterpart, and has a
different honk. An exceptionally large male of the race B. c. maxima,
the "giant Canada goose" (which rarely exceed 8 kg/18 lb), weighed
10.9 kg (24 pounds) and had a wingspan of 2.24 m (88 inches). This
specimen is the largest wild goose ever recorded of any species. The
life span in the wild is 10–24 years.[6]
Distribution and habitat
A flock near a weir on the Humber River near Raymore Park in Toronto, Ontario.
Idaho Falls, Idaho.This species is native to North America. It breeds
in Canada and the northern United States in a variety of habitats. Its
nest is usually located in an elevated area near water such as
streams, lakes, ponds and sometimes on a beaver lodge. Its eggs are
laid in a shallow depression lined with plant material and down. The
Great Lakes region maintains a very large population of Canada Geese.
By the early 20th century, over-hunting and loss of habitat in the
late 1800s and early 1900s had resulted in a serious decline in the
numbers of this bird in its native range. The Giant Canada Goose
subspecies was believed to be extinct in the 1950s until, in 1962, a
small flock was discovered wintering in Rochester, Minnesota, by
Harold Hanson of the Illinois Natural History Survey. With improved
game laws and habitat recreation and preservation programs, their
populations have recovered in most of their range, although some local
populations, especially of the subspecies occidentalis, may still be
declining.
In recent years, Canada Geese populations in some areas have grown
substantially, so much so that many consider them pests (for their
droppings, the bacteria in their droppings, noise and confrontational
behavior). This problem is partially due to the removal of natural
predators and an abundance of safe, man-made bodies of water (such as
on golf courses, public parks and beaches, and in planned
communities).
Contrary to its normal migration routine, large flocks of Canada Geese
have established permanent residence in the Chesapeake Bay and in
Virginia's James River regions, and in the Triangle area of North
Carolina (Raleigh, Durham, Chapel Hill), and nearby Hillsborough. The
parks and golf courses of Scottsdale, Arizona, have an unusually high
concentration of permanent Canada geese.
Alaska
Outside North America
Cambridge, EnglandCanada Geese have reached northern Europe naturally,
as has been proved by ringing recoveries. The birds are of at least
the subspecies parvipes, and possibly others. Canada Geese are also
found naturally on the Kamchatka Peninsula in eastern Siberia, eastern
China, and throughout Japan.
Greater Canada Geese have also been introduced in Europe, and have
established populations in Great Britain, the Netherlands, Belgium,
and Scandinavia. Semi-tame feral birds are common in parks, and have
become a pest in some areas. The geese were first introduced in
Britain in the late 17th century as an addition to King James II's
waterfowl collection in St. James's Park.
Canada Geese were introduced as a game bird into New Zealand and have
also become a problem in some areas.
Behavior
Mid-flight
Looking for food on a partially frozen pondLike most geese, the Canada
Goose is naturally migratory with the wintering range being most of
the United States. The calls overhead from large groups of Canada
Geese flying in V-shaped formation signal the transitions into spring
and autumn. In some areas, migration routes have changed due to
changes in habitat and food sources. In mild climates, such as the
Pacific Northwest and California, due to a lack of former predators,
some of the population has become non-migratory.
Diet
Canada Geese are herbivores although they sometimes eat small insects
and fish. Their diet includes green vegetation and grains. The Canada
Goose eats a variety of grasses when on land. It feeds by grasping a
blade of grass with the bill, then tearing it with a jerk of the head.
The Canada Goose also eats grains such as wheat, beans, rice, and corn
when they are available. In the water, it feeds from silt at the
bottom of the body of water. It also feeds on aquatic plants, such as
seaweeds.[6]
Reproduction
CourtingDuring the second year of their lives, Canada Geese find a
mate. They are monogamous, and most couples stay together all of their
lives.[6] If one is killed, the other may find a new mate. The female
lays 3–8 eggs and both parents protect the nest while the eggs
incubate, but the female spends more time at the nest than the male.
Known egg predators include Arctic Foxes, Northern Raccoons, Red
Foxes, large gulls, Common Raven, American Crows and bears. During
this incubation period, the adults lose their flight feathers, so they
cannot fly until their eggs hatch after 25–28 days.
Adult geese are often seen leading their goslings in a line, usually
with one parent at the front, and the other at the back. While
protecting their goslings, parents often violently chase away nearby
creatures, from small blackbirds to humans that approach, after
warning them by giving off a hissing sound. Most of the species that
prey on eggs will also take a gosling. Although parents are hostile to
unfamiliar geese, they may form groups of a number of goslings and a
few adults, called crèches. The offspring enter the fledging stage any
time from 6 to 9 weeks of age. They do not leave their parents until
after the spring migration, when they return to their birthplace. Once
they reach adulthood, Canada Geese are rarely preyed on, but (beyond
humans) can be taken by Coyotes, Red Foxes, Gray Wolves, Snowy Owls,
Great Horned Owls, Golden Eagles and, most often, Bald Eagles.
Migration
Canada geese are known for their seasonal migrations. Most Canada
geese have staging or resting areas where they join up with others.
Their fall migration can be seen from September through the beginning
of November. The early migrants have a tendency to spend less time at
rest stops and go through the migration a lot faster. The later birds
usually spend more time at rest stops. These geese are also renowned
for their V-shaped flight formation. The front position is rotated
since flying in front consumes the most energy. Canada Geese leave the
winter grounds more quickly than the summer grounds.