Geese
Geese are medium- to large-sized waterfowl known for their distinctive long necks, short legs, and webbed feet, which facilitate swimming. They are primarily vegetarian, consuming a diet of grasses, seeds, and aquatic plants. A notable aspect of their behavior is their strong pair bonds, often mating for life and creating simple nests for their clutches of four to nine eggs. After breeding, geese undergo a molting process that temporarily renders them flightless for about four to five weeks.
Migration is a key characteristic of geese, driven by the need to find suitable habitats as their northern breeding grounds become inhospitable in winter. They migrate in visually striking flocks, often forming V- or U-shaped formations that enhance their aerodynamic efficiency. Geese rely on visual landmarks, celestial navigation, and environmental cues to guide their journeys, which occur in established flyways across North America. Understanding these migratory patterns is crucial for wildlife management and conservation efforts, particularly in determining hunting quotas and wildlife refuge placements.
Geese
Geese Facts
Classification:
Kingdom: Animalia
Subkingdom: Bilateria
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Subfamily: Anserinae
Tribe: Anserini (swans and geese, four genera, thirty-six species)
Geographical location: Primarily the Northern Hemisphere
Habitat: Land (fields, prairies, tundra, forests) and water (ponds, lakes, rivers, streams, inlets, tidal areas, oceans)
Gestational period: From three to four weeks
Life span: Most geese live about twenty years; can (rarely) reach fifty-five years
Special anatomy: Webbed feet, long necks, large bills
Relatively difficult to identify, geese are perhaps best known for their migration, being harbingers of both summer and winter. Geese live comfortably at the intersection of water and land, eating a vegetarian diet of grasses, seeds, roots, berries, and aquatic plants. Unlike many birds, geese pair bond and mate for life, building a simple nest in the ground and lining it with down. Depending on their species, geese lay a clutch of four to nine eggs, and fledglings remain grounded for forty to seventy-three days. Geese molt once a year after the breeding season; during this period, the bird cannot fly for four to five weeks.
Physical Characteristics of Geese
Geese are medium- to large-sized birds, between the size of ducks and swans. They have long necks and short legs in the center of their bodies. Because of this leg placement, geese do not waddle as much as other waterfowl when moving about on land. Their feet are webbed, which enables them to swim rapidly.
The bills of geese have serrations on the mandibles called lamellae; these are useful because most geese gather some of their food while submerged. Because the bill is equipped with a horny covering at the tip of the upper mandible and because of the curved shape of the bill, geese can easily clip grasses, grains, or other foods.
Most species of geese are blackish in color, although many species have considerable white markings in their plumage, often restricted to their bellies or lower tail coverts. Even though each species has distinguishing physical characteristics, it is often difficult to identify a particular species in the field. Even Canada geese, which are probably the easiest to identify with their white chin straps, can be a source of frustration for bird watchers attempting to distinguish between the dozen or so subspecies of Canada geese. Male and female geese of each species resemble each other.
Goose Migration
Many species of birds migrate, but geese, because they are so visible, epitomize this phenomenon to most people. Geese migrate for survival: their northern breeding grounds become inhospitable when water areas freeze over, making food unattainable, and their southern grounds cannot sustain large populations of birds year around. In the United States, geese migrate northward from February to March and southward from September to November.
Geese, like many birds, often return to the same summer and winter areas year after year. Clearly, geese use visual landmarks when migrating; even at night, some landmarks, such as large bodies of water, can be seen from the air. Young geese learn about these landmarks, as well as about traditional migratory stopping places, from their elders. The landscape alone, however, is not all that helps geese navigate. The position of the sun and stars can help them, as can the wind and the earth’s magnetic field.
Most species of geese fly in some sort of V-formation. Flocks of snow geese, for example, form U’s, checkmarks, or irregular masses. Only Canada geese fly in an almost perfect V. These formations have less to do with aesthetics than aerodynamics. Just as bicycle racers will draft lead bikers by riding slightly behind and to the side of them, a goose will draft the lead bird, the one doing most of the work by breaking the wind’s resistance for the birds that follow. Lead birds change during a flight. Geese normally fly at about forty miles per hour, a speed that can change if the bird is in a hurry or being chased.
By plotting the origins and destinations of banded birds, biologists have discovered four main flyways used by geese in the United States: the Atlantic Flyway, the Mississippi Flyway, the Central Flyway, and the Pacific Flyway. Banding geese to study them is more than an academic exercise. Knowing migration paths has allowed experts to make decisions on hunting quotas and on the location of wildlife refuges.
Principal Terms
Banding: attachment of identification tags to individual birds
Clutch: number of eggs in the nest
Coverts: feathers covering the bases of the large feathers of the wings and tail
Fledgling: young bird still unable to fly
Lamellae: toothlike structures in the beak, forming a strainer that permits birds to retain food particles while still enabling water to flow from the closed mouth
Mandibles: upper and lower beak parts
Molting: the loss of feathers that will be succeeded by new growth
Bibliography
Bates, Ashley. “23 Types of Geese Breeds: An Overview (with Pictures).” Optics Mag, 23 Jan. 2023, opticsmag.com/types-of-geese-breeds. Accessed 1 July 2023.
Bellrose, Frank C. Ducks, Geese, and Swans of North America. 3d ed. Harrisburg, Pa.: Stackpole Books, 1980.
Fegely, Thomas. Wonders of Geese and Swans. New York: Dodd, Mead, 1976.
Furtman, Michael. On the Wings of a North Wind. Harrisburg, Pa.: Stackpole Books, 1991.
Lishman, William. Father Goose. New York: Crown, 1996.
Short, Lester. The Lives of Birds. New York: Henry Holt, 1993.