Branta canadensis, Canada goose

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Taxonomy

Taxonomic lineage

cellular organisms - Eukaryota - Fungi/Metazoa group - Metazoa - Eumetazoa - Bilateria - Coelomata - Deuterostomia - Chordata - Craniata - Vertebrata - Gnathostomata - Teleostomi - Euteleostomi - Sarcopterygii - Tetrapoda - Amniota - Sauropsida - Sauria - Archosauria - Dinosauria - Saurischia - Theropoda - Coelurosauria - Aves - Neognathae - Anseriformes - Anatidae - Branta - Branta canadensis

Genus Branta, black geese

Genus Branta belongs to order Anseriformes (waterfowl) that contain a single family Anatidae which include ducks, geese, swans, and screamers. Geese of genus Branta are characterized by prominent areas of black coloration on the head and neck. found in all species. They can be distinguished from all other true geese by their black or very dark grey legs and feet and black bills.

The genus includes the following species: B. bernicla (brent goose), B. canadensis (Canada goose), B. hutchinsii (cackling goose), B. hylobadistes (Nēnē-nui, flightless goose from Hawaii, now extinct), B. leucopsis (barnacle goose), Branta ruficollis (red-breasted goose), B. sandvicensis (Hawaiian Goose or Nēnē), B. sp. giant Hawaiian goose (Giant Hawaiian goose).

Subspecies of species B. canadensis

Subspecies differ in size, shape, coloration and form of beak. However, because of great variation of these parameters within each subspecies, sometimes only very experienced ornithologists are able discern between subspecies with any certainty. Cackling goose (B. hutchinsii) was officially assigned to a separate species only recently in 2006.

Branta canadensis hutchinsii (Lesser Canada Goose)
Branta canadensis maxima (Giant Canada goose)
Branta canadensis minima (Ridgway's Cackling Goose)
Branta canadensis occidentalis (Dusky Canada Goose)
Branta canadensis taverneri (Taverner's Cackling Goose)

Brief facts

• Description

  Adults have a black neck, bill, and head with a white strap under the chin. The body is brownish-gray usually gradually darkening from breast to tail. Females may be slightly smaller than males. The legs are close together with very black feet. These geese have very large wings (127 to 173 cm wingspan) that can also be used as weapons. Depending on the subspecies weight of B. canadensis ranges from 7.1 to up to 18 pounds.
  Giant Canada goose (Branta c. maxima was considered extinct in 1950s until its rediscovery in 1962 by H.C. Nanson). It was described as
  

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  A larger, more elongate bird with considerably longer neck, bill, tarsus and middle toe than the other big subspecies, pale and grayish in colour, the upperparts buffy brown, the underparts very light. It closely approaches canadensis in colour, but it is even paler and less conspicuously barred above; the underparts are more uniform, the base of the hind neck and upper back being not whiter than the rest of the mantle; a white ring at the base of the neck is often present, and a black line on the throat, dividing the cheek patches.

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• Distribution

  Canada geese are found throughout North America. There are southern, northern, western and Aleutian-Canadian populations with one of the subspecies dominating over the others. Populations overlap.
  Canada geese are also found in Europe and were introduced to New Zealand.

• Migration

  Canada Geese are naturally migratory. A general trend in all subspecies is that they spend summers in the northern parts of North America, especially Canada, and migrate south to areas of the United States in the winter months.
  For example, geese that breed and spend summers in Hudson Bay and Ungava Bay, Canada (57° latitude) migrate to wintering areas in New Jersey, Maryland, Delaware, and Virginia (47° - below 40° latitude). Fall migration from breeding locations begin in late September-early October. Monitored birds covered >1,125 km from north of 57° latitude to south of 47° in <7 days, however some birds can cover such a distance in one day. Spring migrations from wintering regions start in late February-March and reach breeding sites by late May.
  In mild climates from California to the Great Lakes, some of the population has become non-migratory due to adequate winter food supply. Non-migrating geese population in Michigan lay eggs in early April and hatching begin in the beginning of May.
  After breeding season and before fall migration, geese undergo annual molting. At the peak of the molting, geese are flightless and keep close to water for swift escape in case of danger.
  Canada geese are birds with lifelong pair bonds and strong family unity and traditions. They migrate in flocks comprised of individual families that stop at the same areas from year to year. Each spring, many adult pairs return to breed in the same areas in which they previously nested. Most arctic-nesting Canada geese do not nest until at least 2 years of age and many subadults are believed to make the spring migration to the breeding grounds in the company of their parents, thus learning the annual migration pattern to and from the natal area. This traditional behavior, plus spatial isolation on the wintering areas, results in restricted breeding between groups, which has fostered the large degree of morphological differentiation exhibited by Canada geese on the continent.
  

• Ecology

  Canada geese are found near waterways in open, grassy habitats such as grasslands, meadows, river basins, lakes, tidal marshes, and arctic tundra. Habitats with water nearby are preferable. They are also attracted to man-made habitats such as golf courses, agricultural land, airports, and parks.

• Diet

  Canada Geese are almost strictly herbivorous.

• Predators

  Main nest predators are gulls (herring gulls Larus argetatus, crows (Corvus brachyrhynchos) and ravens (C. corax), jaegers (Stercorarius spp.), red foxes (Vulpes vulpes), arctic foxes (Alopex lagopus).
  Goslings' potential predators are great horned horned owls (Bubo vorginianus), black-crowned night herons (Nycticorax nycticorax), raccoons, minks, red foxes, dogs, house cats, snapping turtles (Chelydra serpentina), and people. Adult geese are popular game and are hunted by humans.

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Developmental stages (life cycle)

Geese lay 4-6 eggs at rate approx. 1 egg/day (0.7-1.5 egg/day). Canada geese begin incubation gradually, before the clutch is completed, with females becoming progressively more attentive to the nest as eggs are laid. Thus, the period between when the clutch is completed and onset of hatch may not reflect accurate incubation period.

• Embryo Incubation period lasts approx. 27 (range 25-29 days) days starting with the date the last egg is laid and ending when first egg is star- or hole-pipped.
  • Before laying The embryo is located inside the bird.
    • Zygote Fertilized egg, 1-cell embryo, 0 dpc; in oviduct.
    • Cleavage Dividing egg.
      • Early cleavage Takes place in the oviduct
      • Late cleavage Takes place in uterus; shell formation begins.
  • After laying
    • Blastodisc Day 0; blastodisc approx. 5 mm in diameter, showing no elongation.
    • Heart beat,
      head fold Day 3; area vasculosa 20x25 mm, vitellin veins prominent; heart beat, head fold but no tail fold; embryo ~10 mm in size.
    • Limb buds Day 6; iris pigmented; limb buds forming; embryo ~100+ mm.
    • Eyes & limbs
      developed Day 9; eyes and limbs well developed; embryo ~200 mm.
    • Feathers start
      to develop Day 12; Feather papillae on back, rump, and tip of tail; embryo ~500 mm; bill ~6 mm.
    • First feathers Day 15; Feathers on back, flanks, and back of neck; embryo ~700 mm; bill ~9.5 mm
    • Trunk
      feathered Day 18; completely feathered except ventral region of head and neck; embryo ~900 mm; bill ~10 mm.
    • Completely
      feathered Day 21; feather color black and white; embryo ~1,100 mm; bill and feet lightly colored; bill ~13 mm.
    • Dark pigmentation
      on extremities Day 24; dark pigmentation on bill, feet and edge of web; embryo 1,200 mm; bill ~13 mm.
    • Yellow feathers Day 27; feather color yellow; yolk sac 25-50% absorbed; egg can be pipped; bill is very dark; embryo 1,406-1,462 mm; bill ~14.7 mm.
• After hatching
  • Hatchling Until first true feathers (~21 days after hatching). The bird covered by fine down, which remains almost uniformly bright yellow until about 7 days after hatching. Gradually, the down darkens starting from top of body downward; the bird becomes "gawky": legs and feet appear too large. First trace of primary and tail feathers.
  • Fledgling
    • Partly feathered Until ~50 days after hatching until down persists on head and neck; primary feathers 3/4 grown.
    • Fully feathered
      flightless juvenile Until able to fly well at ~ 65 days after hatching. Primaries cross each other over the base of the tail when folded, thus obscuring white upper tail coverts.
  • Subadult Immature bird; until about 3 years of age. One study found that reproductive organs of female birds are immature on 1^st and 2^nd year. Unlike females, the 2-year males exhibit physiological maturity of reproductive organs. However, they usually didn't start mating until 3^rd year.
  • Mature adult Birds with mature reproductive organs, capable of breeding; usually at 2 years of age and older. The onset of behavioral characteristics normally associated with maturity is not necessarily coincidental with physiological reproductive maturity. Lifespan is up to 24 years in the wild and 42 years in captivity.
    • Before pairing The start of courtship is usually announced by honking and recognition displays by established pairs. The birds are restless and fly in small flocks. Unpaired geese sometimes make attempts to approach and examine nests of mated geese. They are usually are not confronted as aggressively as paired geese.
    • Pairing Geese 1-2 years of age usually find a pair during active courting period but may delay nesting until next year. Canada geese are considered to be monogamous. However, some authors reported polygamous tendencies when shortage of males in isolated population occurred. Birds that have lost their spouses usually find new mates.
    • Nesting
      • Nest site choosing The nest requirements include proximity to water, good visibility, firm nest bases, and availability of nest-building material. It was reported that female chooses the nest site.
      • Nest building Female gathers nesting material (grass, leaves, straws, bark, twigs, and sticks) in the nesting site occasionally carrying it for short distance in her bill and make a pile. Then, she excavates a depression of 4-6 inches deep in the nesting material using her bill not long before the first egg is deposited. The nest is carefully maintained during this period.
      • Egg laying Geese lay 4-6 eggs at rate approx. 1.5 eggs/day. Canada geese begin incubation gradually, before the clutch is completed, with females becoming progressively more attentive to the nest as eggs are laid. Thus, the period between when the clutch is completed and onset of hatch may not reflect accurate incubation period. After third or fourth egg, female may add her down to the nest.
      • Incubation Before and during incubation, the gander usually aggressively defends the nesting site and surrounding territory (area depends on status of the goose) from other nesting geese. Intruding unmated geese and passing brood-esccorting geese are usually tolerated much better. During incubation, females usually leave nests twice daily for short period of time to feed and drink.
      • Hatching &
        raising offspring Hatching of all eggs in a clutch usually takes about 24 hours. Parents usually hold hatchlings in the nest for another day for goslings to gain strength and become imprinted to their parents. After leaving the nesting sites, broods maintain their identities for several days. After this period, pairs with young of similar age often gradually loose association and creches, or gang broods, are forming. Creches can be accompanied by several productive pairs and some non-breeding geese may also join.

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Behavior of Canada goose

• Aggression
  • Attack Active charging toward intruder on foot with bill open, hissing; or low flight toward the intruder.
  • Initiated-attack Active movement toward intruder with subsequent slow-down and stopping.
  • Threat-at Intruder is distant, aggressor stretches neck, opens bill but does not charge.
• Retreat
  • Flee Hurry away from the attacker on foot or flying.
  • Low-intensity flee "Casual" movement away from the attacker.
  • Avoidance Fleeing behavior or submissive posture without any threat from potential attacker.
• Male Triumph Ceremony
  • Cackling Neck outstretched, head low to the ground, usually oriented toward mate or family, often associated with "snoring" vocalization; the mate or family responds.
  • Cackling-at Same as Cackling without response from mate or family.
  • Rolling Vigorous rotating and waving movements of the head, often associated with honking.
• Female Triumph Ceremony
  • Facing-away Submissive posture in response to male's cackling.
  • Yipping Irregular staccato sounds of variable pitch.
• Calling Any sustained honking vocalization produced by either sex; distinguishable from Yipping in female geese by its comparatively monotonous, repetitive sounds.
• Head-tossing Vertical flicking of the head communicating the intention to move to a new location.
• Sexual behavior Precopulatory Head-dipping (repeated stereotyped immersion of the head and neck into water), copulation, and precopulatory display (breast, neck, and head tilted backwards, bill upturned).
• Head pumping Repeated lowering and raising of the head in a vertical plane.

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Photo gallery

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Video

Grazing Canada geese (small subspecies)

Gander defends his nest

One swan among Canada geese in winter

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References

• Bruggink JG et al. Nesting and Brood-Rearing Ecology of Mississippi Valley Population Canada Geese Wildlife Monographs No. 126, Jan., 1994, pp. 3-39.
• Trost RE and Malecki RA. Population Trends in Atlantic Flyway Canada Geese: Implications for Management Wildlife Society Bulletin Vol. 13, No. 4 (Winter, 1985), pp. 502-508.
• Malecki RA, Batt BDJ and Sheaffer E. Spatial and Temporal Distribution of Atlantic Population Canada Geese The Journal of Wildlife Management Vol. 65, No. 2 (Apr., 2001), pp. 242-247.
• MONTEREY BIRDS
• Weigand JP, Pollok JM and Petrides GA. Some Aspects of Reproduction of Captive Canada Geese. The Journal of Wildlife Management Vol. 32, No. 4 (Oct., 1968), pp. 894-905.
• Cooper JA and Bruce D. J. Batt DJ. Criteria for Aging Giant Canada Goose Embryos. The Journal of Wildlife Management Vol. 36, No. 4 (Oct., 1972), pp. 1267-1270.
• Yocom CF and Harris SW. Plumage Descriptions and Age Data for Canada Goose Goslings. The Journal of Wildlife Management Vol. 29, No. 4 (Oct., 1965), pp. 874-877.
• Wood JS. Some Associations of Behavior to Reproductive Development in Canada Geese. The Journal of Wildlife Management. Vol. 29, No. 2 (Apr., 1965), pp. 237-244.
• Akesson TR and Raveling DG. Behaviors Associated with Seasonal Reproduction and Long-Term Monogamy in Canada Geese. The Condor. Vol. 84, No. 2 (May, 1982), pp. 188-196
• Akesson TR and Raveling DG. Behaviors Associated with Seasonal Reproduction and Long-Term Monogamy in Canada Geese. The Condor. Vol. 84, No. 2 (May, 1982), pp. 188-196