Canada geese have long black heads and necks, and they have a distinct white mark near their chin. Their plumage includes brown-grey feathers on their back and cream or white feathers on their belly and rump. Males of this species are slightly larger than females, but both weigh between 3 to 10.9 kg. Canada geese are 76 to 110 cm tall, with a wingspan between 1.3 to 1.7 m. Goslings are yellow with grey-green feathers on their back and sometimes their head, depending on the subspecies. They are born with black bills and feet. Their bill has comb-like ridges around the outside edges, which helps them feed. There are seven subspecies, which can be told apart based on their size, plumage color, cheek marks, and collars. The largest subspecies is Branta canadensis maxima, and usually weighs about 6.4 kg. ("Branta canadensis", 2013; Jansson, et al., 2008; Johnson, 2012; "Canada Goose Branta canadensis", 2013; "Canada Goose", 2013; "Canada Goose", 2012; "Canada Goose (Branta canadensis)", 2013)
Canada geese (Branta canadensis) are native to Canada, the United States, and Mexico. They can be found throughout most of North America, but Canada geese usually spend the winter in southern parts of the continent. Although they are originally from North American, Canada geese have been introduced to habitats worldwide including much of Europe, Australia, and parts of Asia, such as Japan, Korea, and Russia. ("Branta canadensis", 2013; Birdlife International, 2012; Jansson, et al., 2008)
Canada geese are usually found in open, grassy habitats. These birds usually avoid areas with tall grass and shrubs because it can hide predators. This species prefers to live near water including ponds, marshes, rivers, or coastlines. Canada geese can be successful at nearly all elevations, from coastal to alpine regions. These birds do well in urban and suburban areas where grassy lawns are maintained. They are also often seen grazing in farmlands. (Conover, 1991; Jansson, et al., 2008; Johnson, 2012; Robinson, 2005; "Canada Goose (Branta canadensis)", 2013)
Male geese are known as "ganders" and females are simply called "geese." Pairs often choose mates that are similar in size, which is known as "assortative mating". Canada geese are monogamous and often remain paired for life. If one mate dies, the remaining partner finds another mate. Pairs of Canada geese with goslings often join other parents in groups called "crèches". They remain together, sometimes until the next breeding season. (Jansson, et al., 2008; "Canada Goose (Branta canadensis)", 2013)
Canada geese breed each year, usually from April to May, but they may continue breeding into June in colder climates. Females build nests and seem to return to the same spots each mating season. Once a female finds a good nesting site, they build a nest with twigs and grasses and insulate it with feathers or down. Although Canada geese become sexually mature at two years of age, they do not usually breed until at least age three. Canada geese raise one brood each mating season and only re-nest if their first brood was unsuccessful. They lay 2 to 10 eggs. Each egg is laid about a day and a half apart and incubation begins once the final egg is laid. The eggs take 28 to 30 days to hatch. Goslings use an "egg tooth," a hard, sharp, tooth-like area on their bill, to help them leave the egg. When the eggs have hatched, the geese often form groups with other parents and their goslings. Goslings leave the nest as quickly as 24 hours after hatching. This allows geese and ganders to lead goslings to food and water shortly after hatching. Although they leave the nest early, goslings are not ready to fly until about 44 days after hatching. At some point during the breeding season, Canada geese molt their feathers and are temporarily unable to fly. This lasts about a month, during which they are very vulnerable to predation. (Jansson, et al., 2008; Johnson, 2012; Robinson, 2005; "Canada Goose (Branta canadensis)", 2013)
In captivity, Canada geese have breed with other geese species, such as greylag geese, snow geese and barnacle geese, to form hybrid goslings. This is less common in nature; however, it may happen when orphaned chicks are adopted by other species, or when geese lay their eggs in the nests of other species. Adopted offspring are raised to be attracted to the fostering goose species, not their own. (Jansson, et al., 2008; "Canada Goose (Branta canadensis)", 2013)
Canada geese have a large parental investment during the first year of their offspring's life. Both males and females are protective of their nest. Once the eggs hatch, males are responsible for defending the nest. Males can be very aggressive against predators and other geese during the mating season. The goslings are fairly well-developed when they hatch, and after only 7 to 10 weeks, they can both fly and find food for themselves. However, juveniles stay with their parents until after they return from spring migration, when the next breeding season begins. (Johnson, 2012; Jansson, et al., 2008)
The average life expectancy for Canada geese can be difficult to determine. In captivity, the longest lived goose was 80 years old. In the wild, the oldest goose was reportedly 30 years and 4 months old. This is an extraordinary lifespan for a wild bird; the life expectancy for most wild geese is 12 years. (Johnson, 2012; Jansson, et al., 2008; Robinson, 2005)
Canada geese fly in a v-formation, known as a "wedge." This flight arrangement is very energy efficient, as is flying with the wind. The lead position in the "wedge" rotates between geese because it is the most taxing flight position in terms of energy use. By flying this way, Canada geese can cover up to 2,400 km in a single day of flight. Flocks of geese are vocal and communicate with each other during flight. ("Branta canadensis", 2013; Johnson, 2012; Jansson, et al., 2008)
Estimating the home range size for Canada geese is difficult because it can vary so much. In some populations, a lone female can have an average home range size of 25 km2. Their home range size increases as the amount of geese in the population increases. Geese that stay in urban or suburban areas all year have smaller home ranges than birds that migration. Canada geese may choose to stay in one location if they can find an area that has few predators and food available in the winter. Likewise, migration is taught by the parents, so if the parents do not migrate, the offspring will also become non-migratory. Birds that do migrate spend spring in their northern breeding territory and winter in their southern wintering range. (Johnson, 2012; Birdlife International, 2012; Cross, 2013; Groepper, et al., 2008; Link, 2013)
Canada geese are known for their honking noise. When they fly, they honk to communicate with each other. The honking noise is generally produced by the male. Females usually give shorter, higher pitched calls. They also hiss when they feel threatened. (Johnson, 2012; Jansson, et al., 2008; McClary, 2004)
To stay healthy, Canada geese should have high protein and high energy diets. They mainly eat leaves, grass, seeds, berries, algae, and roots. The comb-like areas on the edge of their bill helps with grazing, when grass is removed by making a jerking motion with their head. They sometimes eat aquatic invertebrates, insects, small fish, crustaceans, and mollusks, although this is usually during juvenile development, when rearing goslings, or during breeding, when they need more nutrients. If they are unable to find food, Canada geese can go up to 30 days without eating. (Conover, 1991; Jansson, et al., 2008; Johnson, 2012; "Canada Goose Branta canadensis", 2013; "Canada Goose", 2012; "Canada Goose (Branta canadensis)", 2013)
Adult Canada geese do not have many predators because they are so large. If they feel threatened, they will honk and hiss, and sometimes make hostile movements. When left alone, eggs and goslings are much more vulnerable and may be preyed upon by other birds such as gulls, ravens, and crows. Other predators include foxes, wolves, coyotes, bears, dogs, skunks, and raccoons. These birds are also often hunted by humans. (Johnson, 2012; "Canada Goose (Branta canadensis)", 2013)
Canada geese help distribute seeds from the plants they eat, making them important to their ecosystem. Canada geese can also carry many parasites. Gizzard worms are common parasites among many bird species including Canada geese. They can also be infected by the bacterium that causes avian cholera, chlamydiosis, avian botulism, and salmonella. Duck virus enteritis (DVE) is caused by a herpes virus that is thought to be transferred through goose droppings. They can also get aspergillosis, a fungal infection that occurs in birds. (Johnson, 2012; "Duck Virus Enteritis", 2013; "Canada Goose (Branta canadensis)", 2013)
Canada geese are sometimes viewed as pests because they graze on lawns, which leads to the spread of their waste. Large flocks of geese can compact the soil, making it more difficult to grow plants there. It can be very expensive to try and get rid of geese, especially for country clubs and farms. Canada geese can also carry many diseases including: avian influenza, avian cholera, botulism, salmonellosis, chlamydiosis, duck virus enteritis (DVE or duck plague), aspergillosis, and various parasites. Geese can carry these and other parasites, bacteria, and viruses in their feces and spread it to humans or other animals. Large flocks of Canada geese can be a hazard for airplanes. The geese can cause take off and landing delays due to their presence on the runway. In extreme cases, a goose (or many geese) can enter the engine and cause the plane to crash. (Conover, 1991; Jansson, et al., 2008)
Canada geese are often hunted by humans, which provides a recreational activity and food for the hunters. The down feathers from their plumage are also of economic importance, they are used in coats, pillows, blankets, and in numerous other items. (Jansson, et al., 2008)
In 1918, the US Migratory Bird Act took effect, making it illegal to hunt, capture, or kill birds in migration across the United States. As a result, Canada geese can only be hunted during hunting season or with a special permit. However, Canada geese are often killed without permits because the geese are seen as pests in urban areas. These birds are generally seen as a species of little or no conservation concern, as a whole, their population seems to be increasing and is already very large. (Johnson, 2012)
Fauna Yarza (author), Sierra College, Jennifer Skillen (editor), Sierra College, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
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