Branta canadensis

Geographic Range

Canada geese ( Branta canadensis ) are native to Canada, the United States, and Mexico. Although their range covers much of North America, Canada geese generally winter in the southern portion of the continent. Despite their North American origins, Canada geese have been introduced to habitats around the globe. Both intentional introduction and vagrancy are responsible for their introduction to much of Europe, Australia, and parts of Asia, such as Japan, Korea, and Russia.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • introduced introduced
• oriental oriental
  • introduced introduced
• australian australian
  • introduced introduced
• pacific ocean pacific ocean
  • native native

Habitat

Canada geese prefer open, grassy habitats. Areas with obstructions such as tall grass and shrubs are generally avoided because they may disguise 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. Populations of these birds have become well established in urban and suburban areas where grassy lawns are maintained. They are also often seen grazing in agricultural land.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• tundra tundra
• savanna or grassland savanna or grassland
• forest forest

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• coastal coastal

• Wetlands
• marsh marsh

• Other Habitat Features
• urban urban
• suburban suburban
• riparian riparian
• estuarine estuarine

Physical Description

Canada geese can be identified by their long black head and neck, and their bill, which has a distinctive white mark near their chin. Their plumage has varying shades of brown-grey feathers on their dorsal region, and typically a cream or white color on their belly and rump. This species experiences a small degree of sexual dimorphism, where males are slightly larger than their female counterpart, but both weigh between 3 to 10.9 kg. Canada geese have a height of 76 to 110 cm and a wingspan of 1.3 to 1.7 m. Despite small size differences between the sexes, they appear similar. Goslings are yellow with grey-green feathers on their dorsal region and sometimes head, depending on the subspecies. They are born with black bills and feet. Their bill has lamella (comb-like ridges) around the outside edge, to aid feeding. There are seven subspecies, which are distinguished by size, plumage color, white cheek marks, or the presence of a white collar. Among the seven subspecies, the largest is Branta canadensis maxima , and generally weighs about 6.4 kg.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Male geese are referred to as "ganders" and female geese are simply known as "geese." Pairs often select each other based on a similarity in size, which is known as "assortative mating". Often remaining paired for life, Canada geese are monogamous. If one mate dies, the remaining partner finds another mate. Due to their social nature, pairs of Canada geese with goslings often join other parents in groups called "crèches". They remain together, sometimes until the next breeding season.

• Mating System
• monogamous monogamous
• cooperative breeder cooperative breeder

Breeding occurs yearly, generally from April to May, but may extend into June in colder climates. Females are responsible for nest formation and seem to have a preferred mating site they return to each mating season. Upon finding a suitable location, one that is near water and has a favorable vantage point, the female pulls together twigs and grasses to form a nest and insulates it with feathers or down. Although Canada geese reach sexual maturity at two years of age, the first incidence of breeding usually does not occur until at least age three. Canada geese raise one brood each mating season and only re-nest if their initial effort has been unsuccessful. They lay anywhere from 2 to 10 eggs. Each egg is laid approximately a day and a half apart and incubation begins once the final egg is laid. Females occasionally rotate the eggs during incubation. The eggs take 28 to 30 days to hatch. Goslings use an "egg tooth," a hard, sharp, tooth-like projection 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 are precocial and can 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. Despite their ability to leave the nest quickly, fledging does not occur until an average of 44 days after hatching. At some point during the breeding season, Canada geese molt their feathers and are temporarily unable to fly. This period lasts about a month, during which they are particularly vulnerable to predation.

Hybridization between Canada geese and other species, often greylag geese , and sometimes snow geese or barnacle geese have occurred in captivity, but it is thought to be less common in nature. However, the occurrences of hybridization in nature may be explained by brood amalgamation (adoption of orphan chicks) of some goose species, or the nest parasitism displayed by some geese. The adopted offspring are raised to be attracted to the fostering goose species, not their own.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• oviparous oviparous

Among Canada geese, parental investment is high during the first year of their offspring's life. Before the eggs have been laid and during incubation, both males and females are protective of the nest. Once the eggs hatch, males become responsible for defending the nest. Males can be very aggressive against predators and other geese during the mating season. The goslings are relatively well-developed when they hatch, and after only 7 to 10 weeks, they can both fly and find food for themselves. Despite their capabilities, juveniles stay with their parents until after they return from spring migration, when the next breeding season begins.

• Parental Investment
• precocial precocial
• male parental care male parental care
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • male
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • protecting
    • male
    • female
• extended period of juvenile learning

Lifespan/Longevity

It is difficult to determine the average life expectancy for Canada geese. In captivity, the longest lived goose was 80 years old. In the wild, the oldest goose was reportedly 30 years and 4 months old. To have such a long life in the wild is extraordinary; the life expectancy for most wild geese is 12 years.

Behavior

The v-formation used by Canada geese in flight is very energy efficient, as is flying with the wind. This arrangement during flight is called a "wedge" or "skein." The lead position in the "wedge" is rotated because it is the most taxing flight position in terms of energy usage. This technique allows Canada geese to cover up to 2,400 km in a single day of flight. Flocks of geese are often vocal and communicate with each other during flight.

• Key Behaviors
• flies
• motile motile
• migratory migratory
• social social

Home Range

Giving a true description of the home range for all Canada geese is difficult. In some populations, a lone female has a mean home range of 25 km2. The home range size increases as the amount of geese in the population increases. Geese that have become residents of urban or suburban areas have smaller home ranges than birds that participate in migration. There are multiple factors that keep certain populations in one location. With the prevalence of manicured lawns, geese in temperate regions have access to food and a desirable habitat in the winter. Also, the lack of predators in urban environments encourages Canada geese to remain in one location. Lastly, migration is taught to offspring by the parents. If the parental pair does not migrate, the offspring of the couple will become non-migratory. The birds that do migrate spend spring in their northern breeding territory and winter in their southern wintering range.

Communication and Perception

Canada geese are known for their honking noise. During flight, they honk to communicate with each other. The typical honk associated with Canada geese is from the gander. The goose has a shorter, higher pitched call. They also hiss when they feel threatened.

• Communication Channels
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

A proper diet for Canada geese should be high in protein and energy. Their diet can generally be categorized as herbivorous and consists mainly of leaves, grass, seeds, berries, algae, and roots. The lamella on the edge of their bill helps during grazing, when grass is removed by making a jerking motion with their head. Plants containing high amounts of secondary metabolites are avoided, which helps prevent digestive issues and poisoning. Occasionally, aquatic invertebrates, insects, small fish, crustaceans, and mollusks may be dined upon, generally during juvenile development, when rearing goslings, or during breeding, where more nutrients are necessary. If environmental conditions prevent food from being obtained, Canada geese can go up to 30 days without food.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • granivore granivore
  • algivore

• Animal Foods
• fish
• insects
• mollusks
• aquatic crustaceans
• other marine invertebrates

• Plant Foods
• leaves
• roots and tubers
• seeds, grains, and nuts
• algae

Predation

Due to the large size of Canada geese, they do not have many predators. If they feel threatened, honking and hissing will ensue, often joined with hostile movements. Unattended 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. The vast majority of deaths are caused by humans as Canada geese are considered game birds.

Ecosystem Roles

Canada geese are important in their ecosystem as they distribute seeds from the various plants they consume. Canada geese can also carry many parasites. Gizzard worms are common avian parasites and Canada geese are no exception. 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 be victim to aspergillosis, a fungal infection that occurs in birds.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Canada geese were not originally introduced to Europe for hunting, but it quickly became a main purpose for introduction in places like Denmark, Russia, and Sweden. This not only provides recreational activity, but geese can provide 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.

• Positive Impacts
• food food
• body parts are source of valuable material

Economic Importance for Humans: Negative

Canada geese are sometimes viewed as pests because of their tendency to graze on manicured lawns, which leads to unsanitary defecation and potential damage to the ground covering. Large flocks of geese can compact the soil, making it less suitable for further growth. Trying to deter Canada geese from foraging on lawns may have a significant economic cost for some, including country clubs, lawn enthusiasts, and the agricultural community. Canada geese can 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 fecal matter and spread it to humans or other animals. For this reason, their unsanitary fecal matter can be a problem for the management of water sources. 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. The time spent managing waterfowl activity near airports and control towers, as well as aircraft loses, is costly. But the cost of human lives as a result of these accidents is immeasurable.

• Negative Impacts
• injures humans
  • carries human disease
• crop pest

Conservation Status

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 are game birds that can only be hunted during hunting season or with a special permit. Despite this caveat, Canada geese are often killed without permits because the geese are seen as pests in urban areas. Canada geese are generally seen as a species of little or no conservation concern. Although some measures are being taken to control their population, as a whole, the population seems to be increasing and is already very large.

Other Comments

Currently, seven subspecies of Canada geese have been recognized: Branta canadensis Canadensis (Atlantic Canada goose), B. c. fulva (Vancouver Canada goose), B. c. interior (Hudson Bay Canada goose), B. c. maxima (giant Canada goose), B. c. moffitti (Moffitt's or Great Basin Canada goose), B. c. occidentalis (dusky Canada goose), and B. c. parvipes (lesser Canada goose). Branta canadensis canadensis is thought to be the nominate subspecies. Although B. c. maxima is the largest subspecies, B. c. moffitti is similar in size and coloration, the most distinct difference between the species is the white mark on the forehead of B. c. moffitti . In 2004 cackling geese were separated from Canada geese due to mitochondrial DNA evidence.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Fauna Yarza (author), Sierra College, Jennifer Skillen (editor), Sierra College, Leila Siciliano Martina (editor), Texas State University.

References

Birdlife International, 2012. " Branta canadensis (Canada Goose)" (On-line). IUCN Red List of Threatened Species. Accessed May 07, 2013 at http://www.iucnredlist.org/details/22679935/0 .

Conover, M. 1991. Herbivory by Canada geese: diet selection and effect on lawns. Ecological Applications , 1/2: 231-236. Accessed March 16, 2013 at http://www.esajournals.org/doi/abs/10.2307/1941816 .

Cross, T. 2013. "Why have Canadian Geese stopped migrating?" (On-line). Examiner.com. Accessed August 16, 2013 at http://www.examiner.com/article/why-have-canadian-geese-stopped-migrating .

Groepper, S., P. Gabig, M. Vrtiska, J. Gilsdorf, S. Hygnstrom, L. Powell. 2008. Population and spatial dynamic of resident Canada geese in southeastern Nebraska. Human-Wildlife Conflicts , 2/2: 271-278.

Jansson, K., M. Josefsson, I. Weidema. 2008. "NOBANIS - Invasive Alien Species Fact Sheet - Branta canadensis " (On-line). Online Database of the North European and Baltic Network on Invasive Alien Species – NOBANIS. Accessed April 07, 2013 at http://www.nobanis.org/files/factsheets/Branta_canadensis.pdf .

Johnson, S. 2012. "Canada geese ( Branta canadensis )" (On-line). Avian Web. Accessed May 10, 2013 at http://www.avianweb.com/canadageese.html .

Link, R. 2013. "Canada Geese - Living with Wildlife" (On-line). Accessed August 18, 2013 at http://wdfw.wa.gov/living/canada_geese.html .

McClary, R. 2004. "About Canada Geese" (On-line). Citizens for the Preservation of Wildlife, Inc. Accessed August 18, 2013 at http://www.preservewildlife.com/geeseworld.htm .

Robinson, R. 2005. "Canada Goose Branta canadensis " (On-line). BirdFacts: Profiles of birds occurring in Britain & Ireland (BTO Research Report 407). Accessed May 07, 2013 at http://blx1.bto.org/birdfacts/results/bob1660.htm .

Sibley, D. 2010. "Distinguishing Cackling and Canada Goose" (On-line). Accessed August 24, 2013 at http://www.sibleyguides.com/2007/07/identification-of-cackling-and-canada-goose/ .

2013. " Branta canadensis " (On-line). ITIS (Integrated Taxonomic Information System). Accessed April 07, 2013 at http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=174999 .

University of Illinois Board of Trustees. 2013. "Canada Goose ( Branta canadensis )" (On-line). Living with Wildlife in Illinois. Accessed May 09, 2013 at http://web.extension.illinois.edu/wildlife/directory_show.cfm?species=canadagoose .

National Geographic Society. 2013. "Canada Goose Branta canadensis " (On-line). Accessed May 07, 2013 at http://animals.nationalgeographic.com/animals/birds/canada-goose/ .

Seattle Audubon Society. 2013. "Canada Goose" (On-line). Bird Web. Accessed May 10, 2013 at http://www.birdweb.org/birdweb/bird/canada_goose .

The Royal Society for the Protection of Birds. 2012. "Canada Goose" (On-line). The Royal Society for the Protection of Birds. Accessed May 07, 2013 at http://www.rspb.org.uk/wildlife/birdguide/name/c/canadagoose/index.aspx .

State of Michigan. 2013. "Duck Virus Enteritis" (On-line). Michigan Department of Natural Resources. Accessed May 12, 2013 at http://www.michigan.gov/dnr/0,4570,7-153-10370_12150_12220-26644--,00.html .