Branta canadensis

The Canada goose (Branta canadensis) is a large wild goose species with a black head and neck, white patches on the face, and a brown body. Native to arctic and temperate regions of North America, its migration occasionally reaches northern Europe. It has been introduced to the United Kingdom, New Zealand, Argentina, Chile, and the Falkland Islands.[2] Like most geese, the Canada goose is primarily herbivorous and normally migratory; it tends to be found on or close to fresh water.

Extremely successful at living in human-altered areas, Canada geese have proven able to establish breeding colonies in urban and cultivated areas, which provide food and few natural predators, and are well known as a common park species. Their success has led to them often being considered a pest species because of their depredation of crops and issues with their noise, droppings, aggressive territorial behavior, and habit of begging for food, especially in their introduced range. Canada geese are also among the most commonly hunted waterfowl in North America.

Taxonomy and etymology 

The Canada goose was one of the many species described by Carl 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.

Branta is a Latinised form of Old Norse Brandgás, "burnt (black) goose" and the specific epithet canadensis is a New Latin word meaning "from Canada".[4] According to the Oxford English Dictionary, the first citation for the 'Canada goose' dates back to 1772.[5][6][7] The Canada goose is also colloquially referred to as the "Canadian goose".[8]

The cackling goose was originally considered to be the same species or a subspecies of the Canada goose, but in July 2004, the American Ornithologists' Union's Committee on Classification and Nomenclature split them into two species, making the cackling goose into a full species with the scientific name Branta hutchinsii. The British Ornithologists' Union followed suit in June 2005.[9]

The AOU has divided the many subspecies between the two species. The subspecies of the Canada goose were listed as:

• Atlantic Canada goose, B. c. canadensis
• Interior Canada goose, B. c. interior
• Giant Canada goose, B. c. maxima
• Moffitt's Canada goose, B. c. moffitti
• Vancouver Canada goose, B. c. fulva
• Dusky Canada goose, B. c. occidentalis
• Lesser Canada goose, B. c. parvipes

The distinctions between the two geese have led to confusion and debate among ornithologists. This has been aggravated by the overlap between the small types of Canada goose and larger types of cackling goose. The old "lesser Canada goose" was believed to be a partly hybrid population, with the birds named B. c. taverneri considered a mixture of B. c. minima, B. c. occidentalis, and B. c. parvipes. In addition, the barnacle goose has been determined to be a derivative of the cackling goose lineage, whereas the Hawaiian goose is derived from the Canada goose.

Description 

Yellow plumage of gosling

The seven subspecies of this bird vary widely in size and plumage details, but all are recognizable as Canada geese. Some of the smaller races can be hard to distinguish from the cackling goose, which slightly overlap in mass. However, most subspecies of the cackling goose (exclusive of Richardson's cackling goose, B. h. hutchinsii) are considerably smaller. The smallest cackling goose, B. h. minima, is scarcely larger than a mallard. In addition to the size difference, cackling geese also have a shorter neck and smaller bill, which can be useful when small Canada geese comingle with relatively large cackling geese. Of the "true geese" (i.e. the genera Anser or Branta), the Canada goose is on average the largest living species, although some other species that are geese in name, if not of close relation to these genera, are on average heavier such as the spur-winged goose and Cape Barren goose.The black head and neck with a white "chinstrap" distinguish the Canada goose from all other goose species, with the exception of the cackling goose and barnacle goose (the latter, however, has a black breast and gray rather than brownish body plumage).[10]

Canada geese range from 75 to 110 cm (30 to 43 in) in length and has a 127–185 cm (50–73 in) wingspan.[11] Among standard measurements, the wing chord can range from 39 to 55 cm (15 to 22 in), the tarsus can range from 6.9 to 10.6 cm (2.7 to 4.2 in) and the bill can range from 4.1 to 6.8 cm (1.6 to 2.7 in). The largest subspecies is the B. c. maxima, or the giant Canada goose, and the smallest (with the separation of the cackling goose group) is B. c. parvipes, or the lesser Canada goose.[12] An exceptionally large male of race B. c. maxima, which rarely exceed 8 kg (18 lb), weighed 10.9 kg (24 lb) and had a wingspan of 2.24 m (7.3 ft). This specimen is the largest wild goose ever recorded of any species.[13]

The male Canada goose usually weighs 2.6–6.5 kg (5.7–14.3 lb), averaging amongst all subspecies 3.9 kg (8.6 lb). The female looks virtually identical, but is slightly lighter at 2.4–5.5 kg (5.3–12.1 lb), averaging amongst all subspecies 3.6 kg (7.9 lb), and generally 10% smaller in linear dimensions than the male counterparts.[14] The female also possesses a different, and less sonorous, honk than the male.

Distribution and habitat 

In the grass in East Hills, New York

On Spokane River, Washington State

Flock in flight

This species is native to North America. It breeds in Canada and the northern United States in a variety of habitats. The Great Lakes region maintains a very large population of Canada geese. Canada geese occur year-round in the southern part of their breeding range, including most of the eastern seaboard and the Pacific coast. Between California and South Carolina in the southern United States and northern Mexico, Canada geese are primarily present as migrants from further north during the winter.[15]

By the early 20th century, overhunting and loss of habitat in the late 19th century and early 20th century 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.[16] In 1964, the Northern Prairie Wildlife Research Center was built near Jamestown, North Dakota. Its first director, Harvey K. Nelson, talked Forrest Lee into leaving Minnesota to head the center’s Canada goose production and restoration program. Forrest soon had 64 pens with 64 breeding pairs of screened, high-quality birds. The project involved private, state, and federal resources and relied on the expertise and cooperation of many individuals. By the end of 1981, more than 6,000 giant Canada geese had been released at 83 sites in 26 counties in North Dakota.[17] 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 B. c. occidentalis, may still be declining.[citation needed]

In recent years, Canada goose populations in some areas have grown substantially, so much so that many consider them pests for their droppings, 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 near food sources, such as those found on golf courses, in public parks and beaches, and in planned communities. Due in part to the interbreeding of various migratory subspecies with the introduced nonmigratory giant subspecies, Canada geese are frequently a year-around feature of such urban environments.[18]

Contrary to its normal migration routine, large flocks of Canada geese have established permanent residence in Esquimalt, British Columbia, on Chesapeake Bay, in Virginia's James River regions, and in the Triangle area of North Carolina (Raleigh, Durham, Chapel Hill), and nearby Hillsborough. Some Canada geese have taken up permanent residence as far south as Florida, in places such as retention ponds in apartment complexes. Large resident populations of Canada geese are also present in much of the San Francisco Bay area in Northern California. In 2015, the Ohio population of Canada geese was reported as roughly 130,000, with the number likely to continue increasing. Many of the geese, previously migratory, reportedly had become native, remaining in the state even in the summer. The increase was attributed to a lack of natural predators, an abundance of water, and plentiful grass in manicured lawns in urban areas.[19] Canada geese were eliminated in Ohio following the American Civil War, but were reintroduced in 1956 with 10 pairs. The population was estimated at 18,000 in 1979. The geese are considered protected, though a hunting season is allowed from September 1–15, with a daily bag limit of five.