Geese
Geese
Factors affecting the abundance of geese
Geese are large birds in the subfamily Anserinae of the waterfowl family Anatidae, consisting of ducks, geese, and swans.
Geese occur in many types of aquatic habitats, on all continents but Antarctica. Most geese breed in freshwater marshes, salt marshes, or marsh-fringed, open-water wetlands. Geese typically winter in those sorts of natural habitats and in estuaries, although in some regions they also use grain fields in winter, mostly for feeding. Geese are more terrestrial than either ducks or swans, and they typically feed on roots, rhizomes, and shoots of graminoid (grasslike) plants, and on seeds and grains, when available.
Geese are not sexually dimorphic, meaning that there are no obvious, external morphological traits that serve to distinguish between the female, properly named a goose, and the male, or gander. Ganders do tend to be somewhat larger, but size is not a reliable indicator of gender. Like other waterfowl, geese undertake a simultaneous moult of their major wing feathers, and are flightless at that time. This moult occurs during the breeding season, while the geese are taking care of their young.
Most species of goose undertake substantial migrations between their breeding and wintering grounds, in some cases traveling thousand of miles, twice yearly. Flocks of migrating geese commonly adopt a V-shaped formation, which is aerodynami-cally favorable, because it reduces resistance to passage, so less energy is expended in flying. Geese can be rather noisy when flying in groups, which may sometimes be heard before they are seen.
Geese of North America
The seven species of goose that breed in North America are the Canada goose (Branta canadensis ), brant (B. bernicla ), black brant (B. nigricans ), snow goose (Chen caerulescens ), Ross’s goose (C. rossii ), white-fronted goose (Anser albifrons ), and the cackling goose (B. hutchinsii ), recognized as a species separate from the Canada goose in 2004. Two other Eurasian species are occasionally seen during winter: the barnacle goose (B. leucopsis ) on the northeastern coast, and the emperor goose (Philacte canagica ) along the Alaskan coast. The two most abundant species of geese in North America are the Canada goose and the snow goose. The Canada goose is also known as the “honker” because of its resonant call, given especially enthusiastically during migratory flights and while staging. Because of geographic variations in size, morphology, and color patterns, the Canada goose has been divided into about 11 races. However, these races intergrade with each other, and should best be considered to represent continuous, geographic variations of a genetically polymorphic
species. The largest race is the giant Canada goose (B. c. maxima ), of which mature ganders typically weigh about 12.5 lb (5.7 kg). The giant Canada goose has become rather common in some urban and suburban areas, where it has been widely introduced and has established feral, non-migratory, breeding populations. However, because of past overhunting, this race is much less abundant than it used to be in its natural breeding range of southern Manitoba, northwestern Ontario, and Minnesota.
Because of its abundance and widespread migrations, the Canada goose is probably the most familiar goose to most North Americans. During their migrations, the larger-sized races of Canada goose tend to occur in relatively small, often family-sized flocks, and their calls tend to be extended, sonorous honks. Smaller-bodied races flock in much larger groups, ranging up to thousands of individuals, and often flying in large V-shaped formations. These smaller geese have calls that tend to be relatively higher pitched yelps and cackles. Wintering populations of Canada goose often occur as large, dense aggregations in the vicinity of good feeding habitat.
During the era of unregulated market and sport hunting of the nineteenth and early twentieth centuries, the populations of Canada geese were greatly reduced from their historical abundance. This decline was exacerbated by large losses of breeding habitat in the more southern parts of their range, largely due to the conversion of North America’s prairies to agriculture, which was accompanied by the draining of many small, marsh-fringed ponds known as potholes. However, the federal governments of the United States and Canada, and the states and provinces, have since instituted effective conservation measures for the Canada goose and most other species of waterfowl. The most important of these actions is the regulation of hunting effort by restricting the numbers of birds that can be killed, and by limiting the hunting season to a period during the autumn and thereby eliminating the spring hunt, which killed animals before they had an opportunity to breed that year. Also very important has been the designating of a large network of protected areas, mostly to provide essential habitat and refuges from hunting for migrating and wintering waterfowl. In the case of the Canada goose, these measures have proven to be effective, and populations have recovered substantially from lows in the second decade of the twentieth century. At the end of the breeding season and during the autumn migration, North America now supports about three million Canada geese.
At least one million of these birds are subsequently killed by hunters, or by the insidious toxicity of ingested lead shot, or they may suffer natural mortality. Young, relatively inexperienced birds-of-the-year are most commonly killed by hunters, with the more wary adult birds tending to survive this type of predation. This is an important aspect of the hunt, because it results in the reproductive capacity of the population being left relatively intact. It appears that present-day populations of Canada geese are capable of withstanding the intense, annual mortality they are exposed to through hunting and other factors. However, it is important that this situation be continuously monitored, so that any emergent problems are quickly identified, and actions taken to prevent future population declines of this important species of wildlife.
The cackling goose, previously considered one of the smaller races of the Canada goose, was recognized as a separate species based on genetic studies, as well as differences in color, size, voice, habitat, nesting, and migration timing. This relatively abundant species breeds from Canada’s Baffin Island to Aleutian Islands of Alaska and winters from British Columbia south to California and east to northern Mexico and Louisiana.
The snow goose is another abundant species of goose in North America, tending to breed to the north of the major range of the Canada goose. This mostly white goose is often divided into two races, the relatively abundant and widespread lesser snow goose (C. c. caerulescens ) and the greater snow goose (C. c. atlantica ) of the high Arctic. The lesser snow goose has two color variants, the familiar white-bodied form with black wing-tips and the so-called “blue” variant. The blue phase is genetically dominant over the white, and it occurs most frequently in the populations of snow geese breeding in the eastern low Arctic of Canada.
Like the Canada goose, the snow goose has been exploited heavily, and its populations were once threatened by overhunting and habitat loss, especially of wintering habitat. However, strong conservation measures have allowed a substantial increase in the abundance of this species, which, although still hunted, may be approximately as abundant as it was before its intensive exploitation. In fact, since the 1980s, the rapidly increasing breeding populations of snow geese have caused significant degradations of parts of their habitat in the vicinity of Hudson Bay, through overgrazing of important forage species.
Brant and black brant are less common species of goose, occurring in eastern and western North America, respectively. These species are ecologically different from the other North America geese, because of their affinity for estuarine habitats, where they prefer to forage vascular plants known as eelgrass (Zostera marina ). The brant is less abundant than it used to be, because of overhunting and degradations of its wintering habitat, caused in part by occasional declines of its preferred forage of eelgrass. The causes of the eelgrass declines have not been determined, but they may be natural in origin, or somehow caused by human influences, possibly associated with eutrophi-cation. In some years, these geese have also suffered reproductive failures due to unfavorable weather in their northern breeding grounds. This circumstance may also have contributed to the decline of brant.
Economic importance of geese
Like other waterfowl, wild geese have long been hunted for subsistence purposes, and more recently for sport. In recent decades, North American hunters have killed about two million geese each year, although the bag has varied depending on the annual abundance of the birds. About 75% of the geese are typically killed in the United States, and the rest in Canada. Goose hunting is an economically important activity, generating direct and indirect cash flows through spending on travel, guns and other equipment, licenses, and fees paid to hunt on private lands.
Compared with the unregulated, open-access hunts of the past, which devastated populations of all waterfowl and other animals, hunting now appears to be relatively sustainable of the avian resource. Each year the federal governments of the United States and Canada cooperate in setting bag limits on the basis of estimates of the productivity of geese in the breeding habitats. The regulation of the direct kill of geese, coupled with the development of a network of protected areas of breeding, staging, and wintering habitat, appears to be effective in maintaining populations of the most abundant species of geese, while still allowing a large sport hunt.
Two species of goose have been domesticated. The most commonly raised species is derived from the greylag goose (Anser anser ) of Eurasia. This goose has been domesticated for about 4,000 years, and there are a number of agricultural races, most of which are white. Another, less common, domesticated species is the swan goose (A. cygnoides ).
Like ducks and other birds, geese have increasingly attracted the interest of bird-watching, also an activity of significant economic importance.
Geese are sometimes viewed as agricultural pests, because they may invade fields in large numbers during the autumn and spring, raiding unharvested crops or damaging fields of winter wheat (which is sown in the autumn to be harvested in the following summer) and some other crops. These damages can be severe in smaller areas, but can be managed by providing the geese with alternative foods, or by scaring them away.
Factors affecting the abundance of geese
Geese are affected by many of the same environmental factors that influence populations of ducks. Some of these influences are natural. These include the effects of severe weather on the northern breeding grounds of geese, which in extreme cases can wipe out a year’s breeding success. Sometimes, natural predators such as foxes and bears can disrupt breeding in a particular area. When they aggregate in large populations during staging or wintering, geese are also vulnerable to epidemics of diseases such as avian cholera. Natural degradations of staging or wintering habitats may also be important, as may be the eelgrass declines in estuaries used by the brant. As was noted previously for the snow goose, large populations of geese can sometimes degrade their own habitat through overgrazing.
Humans have also greatly affected goose populations. The most important of the negative influences of humans on geese have been overhunting, destruction of staging and wintering habitats, and the toxic effects of ingested lead shot. However, as with ducks, many of these negative influences are now being managed in North America, by controlling the size of annual hunts, by instituting a network of key habitat reserves, and by banning the use of lead shot. These actions have mostly been carried out by agencies of government, as well as by non-governmental organizations, including hunter-focused groups such as Ducks Unlimited, and groups with a conservation mandate, such as the Nature Conservancies.
Humans have increasingly been undertaking activities on behalf of geese and other wildlife. However, these animals are still threatened by many human activities. The eventual balance of the positive and negative interactions of humans and wildlife remains to be determined. Hopefully, the conservation of the populations of all of the world’s species of goose will become an important priority to humans, so that these creatures will always be available to be sustainably harvested, while still maintaining their populations.
KEY TERMS
Feral —This refers to a non-native, often domesticated species that is able to maintain a viable, breeding population in a place that is not part of its natural range, but to which it has been introduced by humans.
Graminoid —Any grass-like plant, usually referring to grasses, sedges, reeds, rushes, and other erect, monocotyledonous species.
Overhunting —The unsustainable harvesting of wild animals at a rate greater than that of recruitment of new individuals, so that the population decreases in size.
Polymorphic —Refers to genetically based variations in shape, size, color, and other traits.
Staging —A characteristic of certain migratory birds, in which individuals collect in large numbers in places with extensively appropriate habitat. Weight gain in staging habitats is important to successful completion of the subsequent arduous, long-distance migration.
Status
- Greater white-fronted goose (Anser albifrons). The population in North America appears to have declined in the 1970s, but to have increased since then.
- Lesser white-fronted goose (Anser erythropus). Alaskan stray. An uncommon species in its native habitat in the Old World, where it seems to be in decline. Has strayed at least once to the Aleutian Islands. Occasional sightings outside Alaska have probably been escapees from captivity.
- Snow goose (Chen caerulescens). The population of the greater snow goose had declined to no more than 3,000 by 1900. In 2002, the global snow goose population was estimated to be 7.6 million. The lesser snow goose population has undergone a pronounced increase in recent decades.
- Ross’s goose (Chen rossii). In 1983, the population in the central Canadian Arctic was estimated to be in excess of 100,000 in 30 colonies. Today, the population appears to still be increasing. This goose frequently hybridizes with the snow goose, but there is no evidence of genetic swamping by that species.
- Canada goose (Branta canadensis). The Aleutian Canada goose is endangered, having almost been exterminated following the introduction of foxes to the Aleutian Islands. The species as a whole has increased its range and population since the 1940s.
- Brant (Branta bernicla). Decline due to disappearance of eelgrass along much the eastern seaboard since the 1930s. Eelgrass has also disappeared in England over the same period.
- Bar-headed goose (Anser indicus). Exotic. Native of Central Asia. Birds that have escaped from captivity in the United States are sometimes seen in the wild.
- Barnacle goose (Branta leucopsis). Eastern stray. Resident of Arctic coasts from Greenland to Siberia, wintering in northwestern Europe. Most strays seen in United States have escaped from captivity, though some occasionally arrive in North America from Greenland.
- Bean goose (Anser fabalis). Alaskan stray. A common goose in northern Asia and Europe, this bird sometimes shows up in Alaska in the spring and, more rarely, in other parts of North America.
- Chinese goose (Anser cygnoides). Exotic. Native of Asia. Domesticated birds in the United States sometimes abandon their home ponds.
- Egyptian goose (Alopochen aegyptiacus). Exotic. Native of Africa. Sometimes escapes from captivity in the United States.
- Emperor goose (Chen canagica). Near threatened. The Alaska population, estimated at 139,000 in 1964, had declined to 42,000 in 1986, but had rebounded to about 84,500 in 2002. The causes of the population fluctuations are not known with certainty, but subsistence hunting and oil pollution are thought to have an impact.
- Graylag goose (Anser anser). Exotic. A native of Eurasia. Rare sightings in the United States have probably been of domesticated birds that have escaped captivity.
- Pink-footed goose (Anser brachyrhynchus). Eastern stray. Many of these birds nest in Greenland and Iceland, migrating to Britain and northwestern Europe where they spend the winter. Strays have been observed a couple of times in eastern Canada.
- Red-breasted goose (Branta ruficollis). Exotic. A native of Eurasia. Birds that have escaped from captivity have been seen in the Northeast.
Resources
BOOKS
Bellrose, F. C. Ducks, Geese, and Swans of North America. Harrisburg, PA: Stackpole Books, 1976.
del Hoyo, J., A. Elliott, and J. Sargatal. Handbook of the Birds of the World. Vol. 1. Ostriches to Ducks. Barcelona: Lynx Edicions, 1992.
Ehrlich, Paul R.; David S. Dobkin, and Darryl Wheye The Birder’s Handbook New York: Simon & Schuster Inc., 1988.
Godfrey, W. E. The Birds of Canada. Rev. ed. Ottawa: Canadian Museum of Nature, 1995.
Heinrich, Bernd. The Geese of Beaver Bog. New York:HarperCollins, 2004.
Johnsgard, P. A. Ducks in the Wild. Conserving Waterfowl and Their Habitats. P-H Reference and Travel, 1993.
Owen, M., and J. M. Black. Waterfowl Ecology. London: Blackie, 1990.
Peterson, Roger Tory. North American Birds. Houghton Mifflin Interactive (CD-ROM). Somerville, MA: Houghton Mifflin, 1995.
PERIODICALS
Henderson, Carol. “A New Goose.” Birder’s World18 (December 2004): 15.
Bill Freedman
Randall Frost
Geese
Geese
Geese are large birds in the subfamily Anserinae of the waterfowl family Anatidae, consisting of ducks , geese, and swans .
Geese occur in many types of aquatic habitats, on all continents but Antarctica . Most geese breed in freshwater marshes, salt marshes, or marsh-fringed, open-water wetlands . Geese typically winter in those sorts of natural habitats and in estuaries, although in some regions they also use grainfields in winter, mostly for feeding. Geese are more terrestrial than either ducks or swans, and they typically feed on roots, rhizomes, and shoots of graminoid (grass-like) plants, and on seeds and grains, when available.
Geese are not sexually dimorphic, meaning that there are no obvious, external morphological traits that serve to distinguish between the female, properly named a goose, and the male, or gander. Ganders do tend to be somewhat larger, but size is not a reliable indicator of gender. Like other waterfowl, geese undertake a simultaneous moult of their major wing feathers, and are flightless at that time. This moult occurs during the breeding season, while the geese are taking care of their young.
Most species of goose undertake substantial migrations between their breeding and wintering grounds, in some cases traveling thousand of miles, twice yearly. Flocks of migrating geese commonly adopt a V-shaped formation, which is aerodynamically favorable, because it reduces resistance to passage, so less energy is expended in flying. Geese can be rather noisy when flying in groups, which may sometimes be heard before they are seen.
Geese of North America
The six species of goose that breed in North America are the Canada goose (Branta canadensis), brant ( B. bernicla ), black brant (B. nigricans), snow goose (Chen caerulescens), Ross's goose (C. rossii), and white-fronted goose (Anser albifrons). Two other Eurasian species are occasionally seen during winter: the barnacle goose ( B. leucopsis ) on the northeastern coast, and the emperor goose ( Philacte canagica ) along the Alaskan coast. The two most abundant species of geese in North America are the Canada goose and the snow goose. The Canada goose is also known as the "honker" because of its resonant call, given especially enthusiastically during migratory flights and while staging. Because of geographic variations in size, morphology, and color patterns, the Canada goose has been divided into about 11 races. However, these races intergrade with each other, and should best be considered to represent continuous, geographic variations of a genetically polymorphic species. The largest race is the giant Canada goose (B. c. maxima), of which mature ganders typically weigh about 12.5 lb (5.7 kg). The giant Canada goose has become rather common in some urban and suburban areas, where it has been widely introduced and has established feral, non-migratory, breeding populations. However, because of past overhunting, this race is much less abundant than it used to be in its natural breeding range of southern Manitoba, northwestern Ontario, and Minnesota. The smallest race is the cackling Canada goose (B. c. minima). Males of this rather dark goose only weigh about 3.5 lb (1.5 kg). This relatively abundant race breeds in the western subarctic, especially in Alaska, and winters in the Pacific Northwest of the United States and southwestern British Columbia.
Because of its abundance and widespread migrations, the Canada goose is probably the most familiar goose to most North Americans. During their migrations, the larger-sized races of Canada goose tend to occur in relatively small, often family-sized flocks, and their calls tend to be extended, sonorous honks. Smaller-bodied races flock in much larger groups, ranging up to thousands of individuals, and often flying in large V-shaped formations. These smaller geese have calls that tend to be relatively higher pitched yelps and cackles. Wintering populations of Canada goose often occur as large, dense aggregations in the vicinity of good feeding habitat .
During the era of unregulated market and sport hunting of the nineteenth and early twentieth centuries, the populations of Canada geese were greatly reduced from their historical abundance. This decline was exacerbated by large losses of breeding habitat in the more southern parts of their range, largely due to the conversion of North America's prairies to agriculture, which was accompanied by the draining of many small, marsh-fringed ponds known as potholes. However, the federal governments of the United States and Canada, and the states and provinces, have since instituted effective conservation measures for the Canada goose and most other species of waterfowl. The most important of these actions is the regulation of hunting effort by restricting the numbers of birds that can be killed, and by limiting the hunting season to a period during the autumn and thereby eliminating the spring hunt, which killed animals before they had an opportunity to breed that year. Also very important has been the designating of a large network of protected areas, mostly to provide essential habitat and refuges from hunting for migrating and wintering waterfowl. In the case of the Canada goose, these measures have proven to be effective, and populations have recovered substantially from lows in the second decade of the twentieth century. At the end of the breeding season and during the autumn migration , North America now supports about three million Canada geese.
At least one million of these birds are subsequently killed by hunters, or by the insidious toxicity of ingested lead shot, or they may suffer natural mortality. Young, relatively inexperienced birds-of-the-year are most commonly killed by hunters, with the more wary adult birds tending to survive this type of predation. This is an important aspect of the hunt, because it results in the reproductive capacity of the population being left relatively intact. It appears that present-day populations of Canada geese are capable of withstanding the intense, annual mortality they are exposed to through hunting and other factors. However, it is important that this situation be continuously monitored, so that any emergent problems are quickly identified, and actions taken to prevent future population declines of this important species of wildlife .
The snow goose is another abundant species of goose in North America, tending to breed to the north of the major range of the Canada goose. This mostly white goose is often divided into two races, the relatively abundant and widespread lesser snow goose (C. c. caerulescens) and the greater snow goose (C. c. atlantica) of the high Arctic. The lesser snow goose has two color variants, the familiar white-bodied form with black wing-tips, and the so-called "blue" variant. The blue phase is genetically dominant over the white, and it occurs most frequently in the populations of snow geese breeding in the eastern low Arctic of Canada.
Like the Canada goose, the snow goose has been exploited heavily, and its populations were once imperilled by overhunting and habitat loss, especially of wintering habitat. However, strong conservation measures have allowed a substantial increase in the abundance of this species, which, although still hunted, may be approximately as abundant as prior to its intensive exploitation. In fact, since the 1980s, the rapidly increasing breeding populations of snow geese have caused significant degradations of parts of their habitat in the vicinity of Hudson Bay, through overgrazing of important forage species.
Brant and black brant are less common species of goose, occurring in eastern and western North America, respectively. These species are ecologically different from the other North America geese, because of their affinity for estuarine habitats, where they prefer to forage vascular plants known as eelgrass (Zostera marina). The brant is less abundant than it used to be, because of overhunting, and degradations of its wintering habitat, caused in part by occasional declines of its preferred forage of eelgrass. The causes of the eelgrass declines have not been determined, but they may be natural in origin, or somehow caused by human influences, possibly associated with eutrophication . In some years, these geese have also suffered reproductive failures due to unfavorable weather in their northern breeding grounds. This circumstance may also have contributed to the decline of brant.
Economic importance of geese
Like other waterfowl, wild geese have long been hunted for subsistence purposes, and more recently for sport. In recent decades, North American hunters have killed about two million geese each year, although the bag has varied depending on the annual abundance of the birds. About 75% of the geese are typically killed in the United States, and the rest in Canada. Goose hunting is an economically important activity, generating direct and indirect cash flows through spending on travel, guns and other equipment, licenses, and fees paid to hunt on private lands.
Compared with the unregulated, open-access hunts of the past, which devastated populations of all waterfowl and other animals, hunting now appears to be relatively sustainable of the avian resource. Each year the federal governments of the United States and Canada cooperate in setting bag limits on the basis of estimates of the productivity of geese in the breeding habitats. The regulation of the direct kill of geese, coupled with the development of a network of protected areas of breeding, staging, and wintering habitat, appears to be effective in maintaining populations of the most abundant species of geese, while still allowing a large sport hunt.
Two species of goose have been domesticated. The most commonly raised species is derived from the greylag goose (Anser anser) of Eurasia. This goose has been domesticated for about 4,000 years, and there are a number of agricultural races, most of which are white. Another, less common, domesticated species is the swan goose (A. cygnoides).
Like ducks and other birds, geese have increasingly attracted the interest of bird-watching, also an activity of significant economic importance.
Geese are sometimes viewed as agricultural pests , because they may invade fields in large numbers during the autumn and spring, raiding unharvested crops or damaging fields of winter wheat (which is sown in the autumn to be harvested in the following summer) and some other crops. These damages can be severe in smaller areas, but can be managed by providing the geese with alternative foods, or by scaring them away.
Factors affecting the abundance of geese
Geese are affected by many of the same environmental factors that influence populations of ducks. Some of these influences are natural. These include the effects of severe weather on the northern breeding grounds of geese, which in extreme cases can wipe out a year's breeding success. Sometimes, natural predators such as foxes and bears can disrupt breeding in a particular area. When they aggregate in large populations during staging or wintering, geese are also vulnerable to epidemics of diseases such as avian cholera . Natural degradations of staging or wintering habitats may also be important, as may be the case of eelgrass declines in estuaries used by the brant. As was noted previously for the snow goose, large populations of geese can sometimes degrade their own habitat through overgrazing.
Humans have also greatly affected goose populations. The most important of the negative influences of humans on geese have been overhunting, destruction of staging and wintering habitats, and the toxic effects of ingested lead shot. However, as with ducks, many of these negative influences are now being managed in North America, by controlling the size of annual hunts, by instituting a network of key habitat reserves, and by banning the use of lead shot. These actions have mostly been carried out by agencies of government, as well as by nongovernmental organizations, including hunter-focused groups such as Ducks Unlimited, and groups with a conservation mandate, such as the Nature Conservancies.
Humans have increasingly been undertaking activities on behalf of geese and other wildlife. However, these animals are still threatened by many human activities. The eventual balance of the positive and negative interactions of humans and wildlife remains to be determined. Hopefully, the conservation of the populations of all of the world's species of goose will become an important priority to humans, so that these creatures will always be available to be sustainably harvested, while still maintaining their populations.
Status
- Greater white-fronted goose (Anser albifrons). The population in North America appears to have declined in the 1970s, but to have increased since then.
- Lesser whitegfronted Goose (Anser erythropus). Alaskan stray. An uncommon species in its native habitat in the Old World, where it seems to be in decline. Has strayed at least once to the Aleutian Islands. Occasional sightings outside Alaska have probably been escapees from captivity.
- Snow goose (Chen caerulescens). The population of the greater snow goose had declined to no more than 3,000 by 1900. In 1988, the snow goose population in eastern Canada was estimated to be 2.4 million, with an annual rate of increase of 130,000/year. The lesser snow goose population has undergone a pronounced increase in recent decades.
- Ross's goose (Chen rossii). In 1983, the population in the central Canadian Arctic was estimated to be in excess of 100,000 in 30 colonies. Today, the population appears to still be increasing. This goose frequently hybridizes with the snow goose, but there is no evidence of genetic swamping by that species.
- Canada goose (Branta canadensis). The Aleutian Canada goose is Endangered, having almost been exterminated following the introduction of foxes to the Aleutian Islands. The population of the species as a whole is probably increasing.
- Brant (Branta bernicla). Decline due to disappearance of eelgrass along much the eastern seaboard since the 1930s. Eelgrass has also disappeared in England over the same period.
- Bar-headed goose (Anser indicus). Exotic. Native of Central Asia . Birds that have escaped from captivity in the United States are sometimes seen in the wild.
- Barnacle goose (Branta leucopsis). Eastern stray. Resident of Arctic coasts from Greenland to Siberia, wintering in northwestern Europe . Most strays seen in United States have escaped from captivity, though some occasionally arrive in North America from Greenland.
- Bean goose (Anser fabalis). Alaskan stray. A common goose in northern Asia and Europe, this bird sometimes shows up in Alaska in the spring and, more rarely, in other parts of North America.
- Chinese goose (Anser cygnoides). Exotic. Native of Asia. Domesticated birds in the United States sometimes abandon their home ponds.
- Egyptian goose (Alopochen aegyptiacus). Exotic. Native of Africa . Sometimes escapes from captivity in the United States.
- Emperor goose (Chen canagica). Threatened. The Alaska population, estimated at 139,000 in 1964, had declined to 42,000 in 1986. The status of the population is not well known, but the population there appears to have declined in the twentieth century.
- Graylag goose (Anser anser). Exotic. A native of Eurasia. Rare sightings in the United States have probably been of domesticated birds that have escaped captivity.
- Pink-footed goose (Anser brachyrhynchus). Eastern stray. Many of these birds nest in Greenland and Iceland, migrating to Britain and northwestern Europe where they spend the winter. Strays have been observed a couple of times in eastern Canada.
- Red-breasted goose (Branta ruficollis). Exotic. A native of Eurasia. Birds that have escaped from captivity have been seen in the Northeast.
Resources
books
Bellrose, F. C. Ducks, Geese, and Swans of North America. Harrisburg, PA: Stackpole Books, 1976.
Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye The Birder's Handbook New York: Simon & Schuster Inc., 1988.
Godfrey, W. E. The Birds of Canada. Toronto: University of Toronto Press, 1986.
Johnsgard, P. A. Ducks in the Wild. Conserving Waterfowl andTheir Habitats. P-H Reference and Travel, 1993.
Owen, M., and J. M. Black. Waterfowl Ecology. London: Blackie, 1990.
Peterson, Roger Tory North American Birds. Houghton Miflin Interactive (CD-ROM), Somerville, MA: Houghton Miflin, 1995.
Bill Freedman Randall Frost
KEY TERMS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- Feral
—This refers to a non-native, often domesticated species that is able to maintain a viable, breeding population in a place that is not part of its natural range, but to which it has been introduced by humans.
- Graminoid
—Any grass-like plant, usually referring to grasses, sedges, reeds, rushes, and other erect, monocotyledonous species.
- Overhunting
—The unsustainable harvesting of wild animals at a rate greater than that of recruitment of new individuals, so that the population decreases in size.
- Polymorphic
—Refers to genetically based variations in shape, size, color, and other traits.
- Staging
—A characteristic of certain migratory birds, in which individuals collect in large numbers in places with extensively appropriate habitat. Weight gain in staging habitats is important to successful completion of the subsequent arduous, long-distance migration.
geese
See also goose, sacred geese, on St Thomas the Divine kill all turkeys, geese and swine.