Canada Goose
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Canada goose ( Branta canadensis ) the Canada Goose
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| ( Linnaeus , 1758) |
The Canada goose ( Branta canadensis ) is a species of bird in the family of ducks (Anatidae) and is considered the most abundant goose in the world . Its original range is North America. There it is a character bird of the lowlands and breeds on inland lakes in the prairie and arable farming areas. Your characteristically V-formation performance-forming train in the winter quarters and return to the breeding grounds in the spring, are in North America symbols for the changing seasons.
In Europe, the Canada goose was in part deliberately introduced. A large part of the populations that exist today, particularly in Great Britain, Ireland, Scandinavia and the Netherlands, can also be traced back to captive refugees. It has also been a breeding bird in Germany since the 1970s.
The Canada goose grows slightly larger than the greylag goose, making it the largest species of geese that can be seen in the wild in Europe.
Appearance
Appearance of adult geese
Characteristic features of the Canada goose are the black head and neck and the extensive white chin band that extends from the throat to behind the eyes. The black throat fletching is set off sharply against the gray chest. Feet and beak are also black. The iris is dark brown. Females and males are colored the same, in some subspecies the gander are significantly larger and longer-necked than the females.
The color of the upper side of the body varies between gray and red-brown, depending on the subspecies. The upper tail-coverts of the geese occurring in Europe as well as the belly and the breast are gray to almost white, the upper side of the body gray-brown. In some of the subspecies to be observed in North America, the underside of the body is also brownish and thus as dark as the flanks.
The body length of the goose is 90 to 100 centimeters, the wingspan 160 to 175 centimeters. The weight varies considerably. Males typically weigh between 3.5 and 6.5 kilograms, while the weight range for females is between 3.0 and 5.5 kilograms. A maximum weight of 7.5 kilograms is reported for the subspecies Branta canadensis maxima .
Appearance of the young birds
The dune dress of the chicks has a yellowish to greenish-yellowish hue, which varies depending on the subspecies. In all subspecies, the headstock, the eye area and the back are olive green. The forehead, face and neck are greenish-yellow. The beak of newly hatched downy chicks is black-gray with a light-colored nail. Legs, feet and webbed feet are dark olive gray. The iris is pale blue-gray. Fledglings have a completely black beak. Feet and legs have the olive-gray color, which is also characteristic of adult Canada geese. The webbed feet are darker than the feet and legs.
The plumage of the young geese is similar to that of the adult. The back and shoulder feathers are, however, more rounded and have a broader brown border. The ventral side is washed out, brownish gray.
Flight image
In flight, the black head and neck and the white throat patch are clearly visible. Some subspecies also have conspicuously white upper and lower tail-coverts, which are also easy to recognize in flight. Due to their size and light front breast, Canada geese can be easily distinguished from barnacle and brent geese, even in flight .
Flying Canada geese are particularly common in the morning and evening hours. The geese stay in bodies of water at night, leave them in the morning to fly to their feeding grounds, and return to the waters in the evening. As a rule, only very short distances are covered on these flights. Research in the UK has shown that Canada geese rarely travel more than three miles.
voice
Canada geese are especially happy to be called during the flight. The call is deep, nasal and trumpeting. It is reminiscent of an “ ah-honk ” or “ a-rong ”, with the emphasis on the second syllable and the pitch rising slightly on this syllable. Canada geese can also identify themselves individually by their call. At large rest areas, a lively shouting can often be heard throughout the night during the train, which helps to find family members. Excited animals call quiik wok or show a sustained, high-pitched shout of triumph in which the calls of the sexes differ. The males call rak-ruk-ruk .... while the females call rak-rak-rak .
The call "Jilk Jilk a-lick" is also described in the literature is characteristic of the subspecies, since 2004, the cackling goose be attributed.
Original distribution area and subspecies occurring there
A number of subspecies are distinguished within their large natural range in North America. The subspecies mix widely in their area of distribution, so that the differentiation between the individual subspecies is not easy and can vary considerably depending on the author. Since the Little Canada Goose ( Branta hutchinsii ) has been classified as an independent species, the division into seven subspecies is the most common. Basically, the subspecies have a darker body color the further west they are in North America. The body size of the respective subspecies, however, increases in the southern direction of distribution.
- Branta canadensis canadensis is the nominate form , which is also known as the Atlantic Canada goose in German. Characteristic of the nominate shape are the light feather hems, which result in weak, but clearly visible bands on the shoulders. The light gray breast plumage becomes lighter towards the neck and is almost white at the beginning of the neck. Towards the flanks, however, the color becomes increasingly yellowish brown. The back, rump and tail are black, while the upper tail-ceiling and the anus region are white. This subspecies of the Canada goose breeds on Anticosti , Nova Scotia , Newfoundland and on Labrador north of the Gulf of Saint Lawrence to the tree line at Webbs Bay on the Labrador Coast. In a westerly direction, their breeding area extends to Ungava on the Hudson Strait . Here their distribution area borders on that of Branta canadensis interior . This subspecies winters near Port Jolí and Port Hébert on Novia Scotia and along the Atlantic coast from southeastern Massachusetts to North Carolina . The number of wintering birds was estimated at around 27,000 in the early 1990s.
- Todd's Canada goose ( Branta canadensis interior ) is a little darker compared to the nominate form. Among other things, the light-colored feather hems on the upper side of the body are narrower. The breast plumage of this subspecies only brightens from a medium gray towards the neck to a dove gray. Their breeding area is in the extensive lowlands around the Hudson Bay, which extends from Manitoba in the east over Ontario to Québec . It also breeds on the islands of the Hudson and James Bay . Akimiski Island and the Belcher Islands , in particular, are known for their stocks of Todd's Canada geese. The wintering area of this subspecies extends from southeastern South Dakota over Missouri to the Gulf Coast of Louisiana and North Carolina. In terms of numbers, this subspecies represents the largest part of the Canada goose population - in the early 1990s the population was estimated at 1.25 million individuals.
- Moffitt's Canada goose ( Branta canadensis moffitti ) is one of the large subspecies. Compared to the nominate form, the entire body is lighter in color. Your body looks a bit squat overall. It also has a relatively short beak and legs compared to the other subspecies. Their breeding area extends from British Columbia , Washington and Oregon , northeastern California , northern Nevada and Utah to Montana and Wyoming . The wintering areas are in Nevada, in central and southern California to the northern region of the Gulf of California.
- The Little Canada Goose ( Branta canadensis parvipes ) is medium-sized and has a light-colored body. In terms of body color and structure, it is largely similar to the Moffit Canada goose, but is significantly smaller. When a number of subspecies were assigned to the new species of Little Canada Goose in 2004, these subspecies were split up and part of the Canada Goose and the other part of the Little Canada Goose. Their scientific names are accordingly " Branta canadensis parvipes " and " Branta hutchinsii parvipes ". The information on body height and weight found in the older literature is therefore no longer reliable. The Lesser Canada Goose is one of the northernmost breeding subspecies found from Hudson Bay to western Canada. The wintering areas are mainly in central California. Individual individual populations move as far as Texas and Mexico .
- The dark Canada goose ( Branta canadensis occidentalis ) is dark all over its trunk. It has a slender body and thinner neck compared to the other subspecies. It breeds on the southern Alaskan coast and winters in the Vancouver and Oregon region .
- The Vancouver Canada Goose ( Branta canadensis fulva ), which also breeds on the northwest coast of North America.
- The giant canada goose ( Branta canadensis maxima ) is the largest of the subspecies. Their body plumage is lighter compared to the nominate form. The neck is very long in relation to the trunk. In some subpopulations of this subspecies it was also found that the neck of the males is 7% longer in relation to the body length than that of the females. In general, there is a significant difference in size between the sexes in this subspecies. Many individuals also have light-colored feathers on the front of the head. In some specimens this white forehead is very pronounced. The ornithologist Hanson , who has studied this subspecies very intensively, also points out that this subspecies also differs in behavior and voice. The birds seldom call during the flight; their reputation is darker than that of the other subspecies. On short flights, they also fly at a lower altitude than other species and their wings flap are flatter. The giant canada goose uses almost the entire North American prairie as a breeding ground. What is certain is that its range stretched from South and North Dakota , Minnesota to Kansas , Kentucky , Tennessee and Arkansas . According to Hanson's research, the giant Canada goose was also found in parts of Colorado , Wyoming and Montana before the population declined due to intensive hunting . It also populated Wisconsin , Illinois , Indiana and Michigan, as well as Alberta and Saskatchewan in Canada and the peripheral areas in southwestern Ontario . Due to the large distribution area, the giant canada goose uses very different wintering areas. The populations in the middle and in the south of the distribution area are partly resident birds. They only migrate south when the lakes in this region freeze over due to cold weather. Winter quarters can be found in California, on the Gulf Coast of Texas, Louisiana, New Mexico and Kansas, among others. There is also evidence of a moulting migration of young birds that are not yet sexually mature and unmated geese in a northerly direction. These birds stay in the lowlands west of Hudson Bay during the moult.
Occasionally, there are references in the literature that small populations of Canada geese are also found in Kamchatka , Japan and eastern China. However, these are subspecies of the Little Canada Goose ( Branta hutchinsii ). The reference to the fact that ring finds show that Canada geese occasionally reach Europe on wandering flights also refers to this species.
habitat
Canada geese require territories that include bodies of water of medium to large size. These have a water depth of at least one meter and ideally also have islands. The prerequisite for establishing a breeding area is an area directly adjacent to the water body on which the geese can graze, as well as a largely undisturbed area on which the nests can be built. Canada geese build their nests on solid ground and prefer places from which the breeding bird can easily observe the adjacent area. In North America, therefore, nests are often found on muskrats' burrows .
In Europe, areas that meet these requirements are mainly parks, park-like areas or pastures bordering lakes. The species has adapted more than in North America to a life in a heavily used agricultural landscape. In North America, the goose is found on the rivers and lakes of wooded and open landscapes.
The requirements for the wintering area are less specific. During this time, the geese can be found both on the coast and inland on stubble fields and grasslands.
Reproduction
Apart from the mating and breeding season, Canada geese live in large schools. Canada geese typically form long-term pair ties. Mating usually takes place in the second year of life, although the geese do not breed successfully until they are three years old.
Courtship and mating behavior
The mating behavior of Canada geese does not differ significantly from that of other geese species. The male initiates courtship behavior by swimming towards the selected female with her neck bent sharply downward. During this impressive behavior, the tip of the beak touches the ganter’s chest. Even if the female rejects attempts by the ganter to mate at this point in time, the male begins to defend the female against other ganter at this stage. After successfully driving away another male competitor, the male shows a triumphant behavior in which it swims to the side of the female. Part of the triumphant behavior is a loud calling into which the female joins when she is interested in the male. Triumphing together plays such an essential role in the pairing behavior of many goose species that the male also drives away imaginary opponents in order to initiate the common triumph. Only after a common triumph does a goose "greet" the ganter: If the ganter swims towards the goose in an imposing position, it also reacts with a strongly bent neck position. The beak also rests on the chest; This posture is interrupted by the occasional immersion of the head in the water. Only then do attempts at mating occur, which can be initiated by both the male and the female. Like most other goose birds, Canada geese typically mate on the water. Mating is preceded by a quick immersion of the head in the water shown by both sexes. This immersion intensifies over a period of 30 seconds to two minutes. The goose swims closer and closer to the goose and usually bites its neck plumage when it mounts it. The goose almost submerges under the weight of the ganter. During mating, the goose spreads its tail feathers upwards and moves its rear body back and forth to allow the two cloaca to touch . After copulation has taken place, the ganter stretches its neck and head and utters a brief call. In doing so, it briefly spreads its wings.
Brood and young birds
The female determines the place where the nest will be built. It is often nothing more than a flat hollow in the ground, which is separated from the environment by a few parts of the plant. However, it is provided with an abundance of down. A great loyalty to the location of the Canada goose has been proven experimentally. Migrating geese return to the areas where they fledged themselves.
Canada geese usually lay between five and six creamy white eggs. However, clutches with two or eleven eggs have also been observed. In the large subspecies, the eggs measure 87 × 58 millimeters; in the smaller subspecies 72 × 48 millimeters. The female breeds alone. However, the male stays near the nest. The breeding season is in early April, occasionally in late March. The young geese hatch after an average of 28 days. The average weight of newly hatched goslings of British populations is about 115 grams. After about 60 to 70 days, the gössel reach their ability to fly. The ganter in particular defends both the goose and the clutch, later the gössel against intruders into the immediate breeding area extremely aggressively. In Canada geese, the intraspecific aggression is more pronounced than in relation to other disturbers. Ganter attack another Canada goose approaching the nest if it falls below 30 meters. Gray geese, on the other hand, are tolerated in closer proximity and are only attacked when they approach the nest more than 15 meters.
The moulting of the parent birds coincides with the breeding season . The swing moult of the parent animals usually begins when the gössel are between three and five days old. Like many species of geese, Canada geese are then flightless for a period of four to five weeks. The regaining of their ability to fly coincides with the time at which their offspring are also able to fly. Most of the time the young stay with the parent animals until the next brood and can often be found with them later.
nutrition
Canada geese mainly live on grass, marsh and water plants in summer. Similar to the gray and brent goose, they also graze underwater plants on a regular basis. The body usually lies horizontally on the surface of the water, while the head and neck are deeply submerged. Canada Geese can significantly increase their underwater reach by lifting their hindquarters out of the water. You keep your balance in this headstand with sometimes very strong paddling movements of your feet. You will then also reach aquatic plants at a depth of 75 centimeters.
In winter they prefer to graze in the country. They prefer parts of the landscape with short grasses and herbs that give them a wide field of vision. Their natural habitat is therefore also characterized by large herbivores - so-called megaherbivores .
hikes
The Canada goose is found in almost all of North America, the southern regions it only uses as wintering quarters. The migration routes of the Canada goose are not genetically fixed, but are handed down in the various subpopulations. Young geese only learn the hiking trail and the location of the winter quarters with their parent birds while they are migrating. Some of the more southern sub-populations are resident birds or partial migrants; the more northerly on the other hand pronounced migratory birds. The more northerly populations sometimes “roll over” the southern populations remaining near the breeding grounds during migration and stay significantly further south than these during the winter half-year.
Life expectancy and predators
The previous record holder among the Canada geese reached an age of 33 years. It was a captive goose. Canada geese usually die much earlier in the wild. Little data is available on their maximum age. Canada geese that live to be older than twelve years in the wild are likely to be the exception. According to American studies, the annual mortality rate in adult Canada geese loyal to their location is around 10%. In the case of geese that moult in the summer and migrate north, the mortality rate is 23%. However, the composition of these two groups is not identical - young, inexperienced geese and those that did not breed are on the move north. In the latter, a weakened condition due to illness and age can be the cause of the lack of breeding success, which also leads to higher mortality on the migration to the moulting areas.
Adult, healthy Canada geese are very rarely struck by predators. Canada geese are vigilant and defensive birds that normally avoid any approach of potential predators by fleeing. They are therefore more likely to be weakened, sick geese that are mainly struck at night by predatory mammals such as red fox , wolf or coyote . During the day, such geese also fall prey to large birds of prey such as the bald eagle . The great horned owl prey mainly on young Canada geese. As a rule, it cannot beat adult geese. Climate conditions that have a negative impact on the food supply tend to influence the population size. After harsh winters, the geese are often in such poor physical condition that this significantly reduces their breeding success. A lack of food in the areas in which the birds come to moult can, in extreme cases, lead to starvation of the birds or affect their fitness so negatively that they cannot survive the winter. Their inability to fly during this time means that they are unable to seek better food grounds. Protozoa seem to be particularly common in Canada geese. These blood parasites can cause high mortality, especially in juvenile birds.
The young geese are exposed to higher pressure from predators. According to individual studies, 2.9 percent of the Gössel die in their first five weeks of life. This is very low compared to ducks such as the mallard and is due to the fact that goose and ganter guard and defend the goslings. Together, a pair of geese can usually successfully ward off attacks by predatory mammals on their brood. However, the absence of one of the parent birds significantly increases the chances of success of predators . In contrast, unfavorable weather conditions have a stronger influence on the chances of survival of the offspring. The higher the amount of precipitation in the first few weeks after hatching, the fewer young geese survive the first three months.
The classification of the pygmy Canada goose as an independent species
In July 2004 the American Ornithologist Union (AOU) decided to assign a number of subspecies of the Canada goose to a separate species. The rearrangement of the species has long been discussed. Some taxonomists had already proposed in the 1970s and 80s to divide the species, which is so variable in body size and plumage, into up to four new species. The differences between the small species that breed in the tundra, which also differ in voice from the subspecies that breed further south, were particularly striking. As a counter-argument, however, it has been repeatedly cited that there are extensive areas in which mixed populations of different subspecies exist. Genetic studies have confirmed the difference between species that breed in the tundra and those found further south. The northern subspecies are more closely related to the other sea geese - especially the brent goose - than to the southern subspecies of the Canada goose. The Little Canada Goose (Branta hutchinsii) has since been recognized as an independent species alongside the Canada Goose. The British Ornithologists Union followed this decision in June 2005.
Since then, the following subspecies are no longer assigned to the species canadensis , but to the species hutchinsii :
- Branta hutchinsii hutchinsii
- Branta hutchinsii asiatica
- Branta hutchinsii leucopareia
- Branta hutchinsii minima
- Branta hutchinsii taverneri
Human and Canada Goose
Naturalization in Europe and New Zealand
Canada geese are now firmly established as breeding birds in both Europe and New Zealand. For problems with the neozoa, see article section Conflict Potential .
The successful reintroduction and recovery of the gray goose coincides in part with a sharp increase in the population of Canada geese. This was possible because there are a number of important differences in environmental requirements between the species. Due to their long neck, Canada geese can still dig into water depths that are not accessible to the greylag goose. The greylag goose also prefers habitats with slightly higher vegetation than the Canada goose for their breeding grounds. The Canada goose tends to be the species that tolerates the proximity of humans more and is more likely than the gray goose to be found in park waters and lakes with high recreational use by humans. In regions with a high density of geese, however, the nesting site competition between the two species is high. There are also hybrids between gray goose and Canada goose. However, the genetic differences between the geese belonging to different genera are so great that these crosses are sterile.
The geese found in Europe and New Zealand cannot be assigned to a specific subspecies. They are a mixture of the subspecies canadensis , interior , maxima and moffitti .
Great Britain
Canada geese were introduced to England as early as the 17th century. Around 1665, agents of King Charles bought the first Canada geese for him. There is evidence that Charles' successor James II also kept them in St. James Park in 1678 as part of his water fowl collection. However, their attitude did not become popular until about a century later, when the change in garden art from a geometrically laid out baroque garden to a spacious landscape garden took place. Large, dammed lakes were typical of these green spaces around the English country estates. In 1762, for example, the well-known British landscaper Capability Brown laid out the large, approximately one- mile- long lake at Holkham Hall . Canada and Egyptian geese were then released on this lake. The feathers of all the offspring of these geese were not trimmed; Parts of these populations already escaped at this point in time and settled in the region around this Norfolk country estate. Something similar happened on other country estates - where large expanses of water were created, swans, geese and ducks were kept and among the species kept were often the robust and tame Canada geese.
1953 was the first time a wild Canada geese count was made in Great Britain. The census only showed a population of 2,200 to 4,000 geese. Most of them were found in the area around Holkham Hall; their numbers were so high there that farmers in this region complained about the damage caused by the geese grazing in the fields. In order to alleviate the problems caused by the high number of geese, parts of the population have been captured and released in other suitable areas. The action was linked with the hope that small groups of geese would prove to be less of a problem. It was also expected that in regions such as Thames Valley , West Midlands and Yorkshire , where ducks and geese are traditionally hunted in autumn and winter, hunting would keep geese numbers down. Both expectations did not materialize, however. The geese, divided into small groups, reproduced more rapidly than before. The geese were hunted and in the 1980s Canada geese made up about 15% of the geese hunted in Great Britain. Only gray goose and short-billed goose accounted for a larger proportion of the hunting range of British hunters, but the hunt had largely no negative effect on the population increase of Canada geese. In 1976 the British population was almost 20,000 and by 1985 39,000 geese. The geese found in Yorkshire also developed moulting behavior - similar to that known from the giant Canada goose in North America. Geese not yet sexually mature, as well as geese whose breeding attempt failed prematurely, migrate north and stay in the summer near Inverness , 500 kilometers north of the breeding area of their subpopulation.
European continent
For the year 1785 Canada geese are also recorded as ornamental poultry on the European mainland. The motives for keeping them were similar to those in Great Britain - the large lakes of the newly created landscape parks required “revitalization” with water fowl, and geese and ducks were kept in addition to the aesthetically particularly attractive swans. Similar to the UK, the Canada goose did not begin to spread widely in Europe until the middle of the 20th century. Escaped geese from ornamental poultry farming contributed to this, as did targeted reintroductions. The ornithologist Bengt Berg , for example, brought Canada geese to the Kalmar Strait in south-east Sweden in the 1930s . These geese released into the wild are considered to be the most important stock population of the geese now native to Scandinavia. The significant increase in the European population, which was accompanied by a significant expansion of the breeding area, began in the 1960s. In 1970 the first geese brood in Norway and a little later in Finland and Denmark . In the 1980s, for example, there were already 3,000 Canada geese in Finland that migrated south in winter. Since 1950 Canada geese have been observed as migrants and winter guests (mid-October to the end of March) in the north of the FRG. At the beginning of the 1990s between 400 and 600 breeding pairs had established themselves in Germany. For 2005, 1,500 breeding pairs and more than 6,000 individuals were reported. For 2010, 60,000 breeding pairs and 350,000 individuals were given for Europe.
New Zealand
Unlike in Great Britain and continental Europe, Canada geese were not imported into New Zealand as ornamental fowl, but as game. Here, too, it was mainly the subspecies from eastern North America that were introduced. The Canada goose is now found all over New Zealand, whereby it was able to spread particularly strongly in the south of New Zealand.
The first Canada geese were released in New Zealand in 1876 and 1879. However, this stock could not establish itself. The current population in New Zealand is largely traced back to 50 Canada geese that were released to the South Island in 1905. Further reintroductions were made until 1920. In 1925, this goose was in the regions of Otago and Canterbury in New Zealand declared a wild game. Here, too, the hunt for Canada geese did not prove to be a population-limiting factor. As early as the 1950s, New Zealand farmers began to complain about pasture damage caused by these geese. The New Zealand Wildlife Service shot 3,000 geese to contain agricultural damage as early as 1950, but the population number was 20,000 individuals in the late 1980s. The fact that the living conditions in New Zealand differ only slightly from those in North America contributed significantly to their success in spreading. New Zealand farmers have also imported grass species from the northern hemisphere, which the Canada geese use as fodder there.
Canada geese are part migrants in New Zealand. While some populations overwinter near their breeding sites, the large numbers of Canada geese that breed on Lake Ellesmere move to the north of the South Island from late August. Non-breeding adult Canada Geese return to Lake Ellesmere to moult in early December. The Canada geese, which successfully breed on this lake, and the young birds return from March to May.
Total stock
The IUCN puts the total population of the species at 1 to 10 million animals and classifies the species as harmless.
hunt
Little is known about the hunting of Canada geese by indigenous North American peoples prior to the introduction of the rifle. For the Cree Indians in the Hudson Bay region, the Canada goose was still an important part of the diet, at least in the 1950s, when other foods were not available in the spring. Whether this also applies to the time before the settlement by European settlers, the associated changes in the North American biosystem and, above all, before the introduction of firearms, has at least not been proven. However, like all geese, Canada geese are attractive prey simply because of the amount of meat they represent. Hunting a goose with a bow and arrow is uneconomical; the probable loss of the elaborately manufactured arrow in the water usually outweighs the gain of only potentially possible hunting prey. Moulting and therefore flightless geese were more accessible to humans. The Eskimos in northern Canada, Alaska and northeastern Russia traditionally hunted flightless geese. Their hunting techniques are still used today to ring Canada geese. The behavior of the flightless geese is so predictable that they can "drift". A trapping system made of nets is set up at a suitable location and the geese are driven into this trapping system by a group of people on foot or in boats.
The hunt for geese with rifles intensified from the late 18th century and continued to grow as rifles became more reliable and more accurate. Dog breeds such as Labrador Retriever , Chesapeake Bay Retriever, and Golden Retriever are dog breeds specifically bred for hunting water fowl. In North America, the hunt for Canada geese became a popular sport in which the hunters tried to outdo each other by killing the heaviest goose. The ornithologist Harold C. Hanson, who rediscovered the giant Canada goose, which was believed to be extinct, attempted to reconstruct its original range on the basis of hunting reports of unusually heavy Canada geese. The extent to which the decline in populations of this subspecies is due to hunting can no longer be determined. The change in their habitat as a result of increasing human settlement certainly had a major influence on the population.
In Europe, at least, the Canada geese population could not be regulated by hunting. In Great Britain, part of the Canada goan population is not huntable because they are too close to humans. In other regions, the Canada goose has even benefited from hunting: In New Zealand it was introduced specifically because the aim was to use it to establish attractive game. In Sweden it benefited in its population development from the targeted offer of nesting aids by hunters. Not least because of this, it is now the most common and widespread goose in Sweden.
Potential for conflict
Disease transmission
On the occasion of an inquiry in the state parliament of Baden-Württemberg , it was stated in 2015 that Canada geese (like other species of real geese ) are known to be carriers of numerous pathogens. Salmonella in particular is to be expected in these species. Legal requirements for control are not known. With the spread of this species there is a risk of spreading pathogenic germs. The species is potentially seen as a vector for diseases such as avian influenza, botulism, salmonella, cerkaria and pathogenic protozoa, transmission via pollution through faeces, decay of lawns, playgrounds and water in bathing waters. Against this background, discussions about bathing bans became known several times.
Agriculture
Most of the wild goose species can cause significant damage to pastures and grain fields. Farmers are compensated for this in many regions today. But this is not the case everywhere. For example, the Free State of Saxony does not pay any compensation for loss of income that can be traced back to geese or swans. When determining the amount of damage, factors as diverse as the duration of grazing, the time, the crop affected, weather conditions and soil conditions must also be taken into account. Geese grazing on agricultural land do not necessarily cause damage - studies have shown that the yield of a field can increase by up to 10 percent after geese grazing, if the ground is dry or frozen and the grain plants have already sprouted the fourth or fifth leaf. The grazing then leads to better tillering of the plants and thus higher crop yields. It has a negative effect on the yields of the field, the more humid the soil and the younger the germinated seed was at the time of grazing. On very wet and soft soils, even highly developed cereal plants, which under other conditions would benefit from geese grazing, can be pulled out by the geese nudging movement. Even more damaging under these soil conditions is the compaction of the soil by the goose step . In places where a lot of geese pass, the soil can become so compact that cereal crops die due to a lack of soil ventilation. Canada geese damage is more difficult to measure in pastures. As a rule of thumb, however, five Canada geese have roughly the same nutritional requirements as a sheep.
The year-round presence and high population density of the Canada goose generally creates a higher potential for damage than wild goose species that only appear on agricultural land at certain times of their migration - farmers have fewer opportunities to limit possible damage from a different crop rotation or changing the cultivation times. Canada geese, for example, can be found in grain fields that are almost ready to be harvested in order to eat the ears empty. The cobs of maize plants that have been depressed by wind or rain are occasionally harvested from them. Like other geese, Canada geese are able to tap new food sources quickly and damage pasturage and grain areas as well as tomato plantations, cabbage, sugar or carrot fields. In places where Canada geese can be found all year round, defensive measures such as scarecrows or plastic bands or aluminum strips fluttering in the wind are also more difficult to establish. Geese recognize in a relatively short time when they pose no real danger. In British experiments with a human-like scarecrow that was battery-powered and moved arms and head at irregular intervals, geese had classified them as harmless within 14 days that they were grazing in their immediate vicinity.
In order to avoid agricultural damage, the hunting of Canada geese has been increased continuously since 2007.
Ecosystems
Canada geese also inhabit parks and park-like areas. The large amounts of feces they leave behind pollute paths and lawns and eutrophicate the water. The geese, which are much more aggressive during the breeding season, can also restrict their use by humans. Due to the high level of aggressiveness, other water birds can be driven away from their breeding grounds or settlement can be prevented. This can lead to undesired hybridization with the gray goose. There is food competition with native geese and the wigeon . Reeds can be eaten up in such a way that they are unsuitable as a habitat, here breeding ground, for reed birds. For Germany, the elimination (catching and shooting) of local stocks is required so that no larger populations build up. A Europe-wide fight does not seem feasible because of the effort involved.
air traffic
Due to their high weight make Canada geese a danger to air traffic. Thus, an Airbus A320 had to Hudson River ditch after shortly after taking off several Canada geese in his turbofans had fallen and these turned out by (see US Airways Flight 1549 ).
With the microlight to the south: trained behavior
In the fall of 1993, the sculptor William Lishman succeeded in taking a small flock of human-reared Canada geese from Ontario to wintering areas in Virginia in an microlight. Almost all of these geese returned to the farm on which they were raised in the spring of 1994. He repeated the experiment in 1994 with an even larger group of geese, for which a wildlife sanctuary in South Carolina, further south, was chosen as wintering quarters. This second experiment, which was scientifically accompanied by biologists and nature conservationists, was also successful. With this pioneering act he was able to show that there are possibilities to train migratory birds reared in an artificial environment to move naturally. This is essential for the conservation of threatened species of migratory birds such as trumpeter swans and whooping cranes . These species are endangered by the fact that their wintering areas have been destroyed or that they use routes on their migration where they are particularly endangered. Sometimes there is only a population of these species that is limited to a single area. Experience with endemic species such as the Puerto Rican Wood Warbler or the Puerto Rican Amazon has shown that a single natural disaster or disease outbreak can dramatically affect the number of individuals of such a species and lead to complete extinction of the species. To reduce this risk, it can make sense to repopulate suitable habitats with parts of the existing population. Ideally, the new habitat offers such good conditions that the reproduction rate of a species also increases significantly.
While resettlement was a conservation strategy that had been practiced successfully for several decades for resident birds, it was not considered to be very promising for migratory birds with learned migration routes. Until Lishman's successful experiment with Canada geese, there seemed to be no way to train them to migrate adequately.
Lishman's flight with the Canada geese was the inspiration for the film Amy and the Wild Geese , in which the young titular heroine takes her hand-reared Canada geese to a suitable wintering habitat in an ultralight aircraft. Wildlife filmmakers now also use light aircraft for their recordings to take close-up shots of birds in flight. Films like Nomads of the Skies - The Secret of the Migratory Birds are only possible through recordings made from light aircraft.
literature
- Hans-Heiner Bergmann , Helmut Kruckenberg, Volkhard Wille: Wild geese - travelers between wilderness and pastureland. G. Braun Verlag, Karlsruhe 2006.
- Frisian Association for Nature Conservation and Ecological Hunting: Focus on the geese problem. (online PDF ), 2016.
- Society for Nature Conservation and Ornithology Rhineland-Palatinate (GNOR): Goose monitoring for gray and Canada goose. 2008, online PDF
- Jesper Madsen, Gill Cracknell, Tony Fox: Goose Populations of the Western Palearctic. Wetlands International, Wageningen 1999.
- Steve Madge : water fowl. An identification book of the swans, geese and ducks of the world. Verlag Paul Parey, Hamburg 1989, ISBN 3-490-19018-1 .
- Harold C. Hanson: The Giant Canada Goose - Revised Edition. Illinois Natural History Survey.
- Myrfyn Owen, GL Atkinson-Willes, DG Salmon: Wildfowl in Great Britain. Cambridge University Press, Cambridge 1986, ISBN 0-521-30986-7 .
- Janet Kear : Man and Wildfowl. Poyer, London 1990, ISBN 0-85661-055-0 .
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds. Volume 1. Ratites to Ducks. Oxford University Press, Oxford 1990, ISBN 0-19-553068-3 .
- Erich Rutschke: The wild geese of Europe - biology, ecology, behavior. Aula Verlag, Wiesbaden 1987, ISBN 3-89104-448-8 .
- Erich Rutschke: Wild geese - way of life, protection, use. Parey Buchverlag, Berlin 1997, ISBN 3-8263-8478-4 .
- Malcolm Ogilvie, Bruce Pearson: Wildfowl Behavior Guide. Hamlyn, London 1994, ISBN 0-600-57973-5 .
- William Lishman: Father of the Geese - On the trail of the secret of bird migration. Droemersche Verlagsanstalt, Munich 1996, ISBN 3-426-26908-2 .
Web links
- Branta canadensis in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 30 of 2009.
- English article about the separation of the Little Canada Goose as a separate species
- Homepage of the Canada Geese Community
- Canada goose feathers
Individual evidence
- ↑ Rutschke, Wildgänse - way of life, protection, use , p. 90
- ↑ Hanson, pp. 15-17
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0-00-713039-2 , p. 68
- ↑ Kolbe, p. 121
- ↑ Owen, p. 380
- ^ Hans-Heiner Bergmann, Hans-Wolfgang Helb, Sabine Baumann; The voices of the birds of Europe - 474 bird portraits with 914 calls and chants on 2,200 sonograms. Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1 , p. 38
- ↑ Madge, p. 146
- ↑ Madge, p. 146
- ↑ Hanson, p. 145
- ↑ Rutschke, p. 79
- ↑ Ogilvie, pp. 86f
- ↑ Hanson, pp. 145 f
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0-00-713039-2 , p. 68
- ↑ Collin Harrison, Peter Castell: Field Guide Bird Nests, Eggs and Nestlings. Harper Collins Publisher, 2002 revised edition, ISBN 0-00-713039-2 , p. 68
- ↑ Alfred Limbrunner, Einhard Bezzel, Klaus Richarz, Detlef Singer: Encyclopedia of breeding birds in Europe . Franckh-Kosmos, 2007, p. 124, ISBN 978-3-440-11110-9 .
- ↑ Kolbe, p. 120
- ↑ Hanson, p. 113
- ↑ Rutschke, p. 125
- ↑ Kolbe, p. 121
- ↑ Ogilvie, pp. 18f
- ↑ Rutschke, p. 184
- ↑ Rutschke, p. 184
- ↑ Rutschke, p. 185
- ↑ Rutschke, p. 181
- ^ Kear, p. 184
- ↑ Kolbe, p. 120
- ^ Kear, p. 148 and p. 182
- ↑ Owen, p. 382
- ↑ Kear, p. 110
- ↑ Kear, p. 182ff.
- ↑ Kolbe, p. 123
- ↑ Klemens Steiof: Action requirements in dealing with non-native and invasive bird species in Germany . Reports on bird protection 47/48, 2011: 93–118.
- ^ Higgins, p. 1190
- ^ Higgins, p. 1191
- ^ Kear, p. 184
- ^ Higgins, p. 191
- ^ Hanson, p. 144
- ↑ Ogilvie, pp. 55f
- ↑ Hanson, pp. 3 to 103
- ↑ State Parliament of Baden-Württemberg: Printed matter 15/678923. 04. 2015 (online PDF)
- ↑ Species profile Canada goose (accessed July 19, 2019).
- ↑ Lambsheim: District issues bathing ban for nocturnal ponds
- ↑ Canada geese: Bathing is threatened at Lake Horstmar
- ↑ Pollution by geese: The Elfrather See in Krefeld is no longer bathing water
- ↑ Saxon State Office for Environment and Geology (ed.): Wild geese and swans in Saxony - occurrence, behavior and management , Dresden 2006, publication as part of the public relations work of the Saxon State Office for Environment and Geology, p. 6
- ↑ for a more detailed description of the potential for conflict between geese and agriculture s. for example Rutschke, pp. 211 to 223
- ↑ Owen, p. 382
- ↑ Owen, p. 380
- ↑ Rutschke, p. 221
- ↑ Frisian Association for Nature Conservation and Ecological Hunting: Focus on the geese problem (online PDF) ( Memento from September 30, 2017 in the Internet Archive )
- ↑ Klemens Steiof: Action requirements in dealing with non-native and invasive bird species in Germany . Reports on bird protection 47/48, 2011: 93–118.
- ↑ National Transport Safety Board: Loss of Thrust in Both Engines After Encountering a Flock of Birds and Subsequent Ditching on the Hudson River , p. 48f / Chapter 1.16.2 “Biological Material Sampling and Analysis”, Washington, May 4, 2010
- ↑ Lishman, pp. 172-213
