Bird Families

Northern Gannet (Maurice busanus) Bird Profile

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The Northern Gannet, scientific name, Maurice busanus is a marine bird, the largest species of the Gannet, Sulidae. It is native to the coast of the Atlantic Ocean, breeding Western Europe and North America. Also called solan goose, Northern Gannet is available in Canada, Greenland, Iceland, and northeastern Europe, wintering to the Gulf of Mexico, Morocco, and the Mediterranean.

The adult northern Gannet has a long, long, narrow right basal white-flowing body. It is 170-180 cm (67-71 inches) long and 87-100 cm (34-39 inch) long.

The head and nape have a buff tinge that is more obvious during the breeding season and the wings are dark brown-black feathers. The long pointed bill is blue-gray, with black nude skin around the face and eyes.

Adolescents are mostly gray-brown, gradually turning white within five years, and it takes them to reach maturity.

Nesting colonies on both sides of the North Atlantic, Scotland, the largest of which are Bass Rock (twin pairs as 0), St Kilda (601,2 pairs as 27) and Ailsa Craig of Scotland (5.7 pairs), Gresholm and Bonaventure in Wales The island (60,000 pairs in 20) is located on the coast of Quebec.

Its breeding boundaries extend to the north and east, on the Kola Peninsula of Russia in 8 and Bear Island in the southernmost island of Svalbard in the 20th.

The colonies are mostly located along the cliffs on the coastal island, from which birds can more easily enter the air. The Northern Gannet manages the al tu migration and hunts for fish that form its dietary diet by submerged in high seas.

Gannet was hunted for food in some parts of its range and is still practiced in the Outer Hebrides and Faroe Islands in Scotland.

It faces a number of threats, either natural or man-made, and as its population grows, the International Union for Conservation of Nature (IUCN) considers it a less worrisome species. As an obvious and common bird, it is mentioned in several ancient myths and legends.

Description

An adult Northern Gannet has wings of 170-180 cm (67-71 in), and is 87-100 cm (34-39 in) long and weighs 2.5-1. kg (5.7-3 lb), making it the largest gannet and the largest marine native to the western Palearctic.

The two sexes are generally of the same size and appearance. The plumage is dark brown to black with tips of black wings.

The primary flight feathers, the primary cover and the potato are dark. The tinned buff-yellow color is on the head and neck, becoming more prominent during the breeding season.

Women are darker in color than men. Eye to light blue to light gray iris is surrounded by a thin black ring of bare skin.

The edge is long, strong, and conical, with a light down and a sharp cutting edge. In adults, the shaft is blue-gray and dark gray or black-edged. There is a black notch of mandatory length that blends into the skin around the eyes.

A black band of bare skin separates the pale feathers of the forehead and neck from the bill, which gives Gannet the mark of her distinctive face. Four-legged legs are joined by a membrane that can vary in color from dark gray to dark brown.

The colored lines continue along with the toes that continue up to the feet. They are usually greenish-yellow in males and blue in females and probably play a role in mating.

The young bird is showing adult plumage with the front of its body.

The fledglings are dark gray to slate-gray and the upper parts and wings are finely dispersed with white. At the bottom of the ramp are prominent V-shaped white areas with area wings and tailings dark brown-black, partially tipped with white.

Bill and Iris are dark browns. They can weigh more than 4 kg (8.8 lbs) when leaving the nest at about 10 weeks of age.

In the second year, the appearance of the birds varies depending on several steps: They can get adult plumage in the front and continue to be brown in the back. By the time he matured five years later, the Gannets gradually gained more white in later seasons.

The northern gannets are somewhat larger and thicker-billed than the cape or Australian gannet- the wings of the northern gannet have more whites and a whitish-white tail, the other species have black tips of tail feathers.

Individuals on the west coast of Africa may be confused with Wanger mask boobies, although the end is overall smaller, the head does not have a bunch of buffs, and has a black tail.

From afar, or with low visibility, albatrosses can be confused with northern gannets, especially immature feathers whose wings are more black.

Adaptation for diving

Northern Gannet has streamlined bodies adapted for high-speed immersion diving, with stiff neck muscles and a spongy bone plate at the base of the bill. Nasarica is inside the bill and can be closed to prevent water access.

The eyes are protected by powerful imaginary membranes. There is a subcutaneous air sac on the lower body and the sides. Other air sacs are located between the sternum and pectoral muscles and between the ribs and the intercostal muscles.

These sacs are attached to the lungs and when the bird breathes in the air, the air can return to the lungs by contraction of the muscle.

Feathers are waterproof, which allows birds to spend a longer time in the water. The immense drainage produced by a voluntary gland covers the fins, and the birds use their scalp or head to spread it throughout the body.

Individuals have a subcutaneous fat level, feathers below are thicker and have tightly overlapping feathers that help them withstand low temperatures.

Reducing blood flow by shaking their legs outside the breeding season helps the birds maintain body temperature while swimming.

Call

The Northern Gannet is a lofty and vowel bird, especially in the colony. Its general call is a rigid Arara-Arara or Urarah-Urarah, which is emitted when arriving or challenging the other colony of the colony.

When fishing or collecting nesting material, the call is shortened to a rah and the time to close is ooo-ah. The calls for sex are the same.

According to Nelson, the northern genitals recognize their breeding partners, their rooftops, and the call of the birds in the wings. Individuals outside this field are treated with further aggression.

Distribution and Accommodation

The fertility range of North Gannett is on the coast affected by the Gulf Stream, on the coast of the North Atlantic, on the Gulf of St. Lawrence and on the islands off the east coast of Canada. They usually nest in large colonies overlooking the sea or on small rocky islands.

The water needs to be cool enough for Atlantic mackerel and herring to be the main food source for the Northern Gannet. These regions also extend beyond the continental shelf.

The Northern Gannet colonies are found very north in the winter and stormy regions, and Nelson suggests that they can survive in these regions for a number of reasons, including a combination of body weight and a strong movement that allows them to capture the strongest.

Muscular fish and the ability to catch prey far from the cage. Their fat reserves act as weights and archives during extended periods without food when diving.

The northern Gannet limits of their breeding areas depend on the presence of ice-free waters in the sea during the breeding season.

Thus, while Greenland and Svalbard provide suitable breeding sites, summers in the Arctic region are so low that northern janitors lay their eggs and raise a brood, which needs between 26 and 30 weeks.

The southern Gannet limit of their distribution depends largely on the presence of sufficient prey. There is fossil evidence of Northern Gannet breeding in the Pleistocene Crete.

Breeding colonies

Several northern Gannet breeding colonies have been recorded as being located in the same place for several hundred years. When flying cliffs are seen at short distances, white is seen because of the number of nesting birds on them.

There has been a written record of the colony on the island of Londi since 1220. By 1818 there were only 70০ nests, and finally, the colony disappeared in the 5th. More than two-thirds of the world population eds off the coast of the British Isles

Travel

After the breeding season, adult northern genitals spread over a wide area although they did not travel more than 800 to 1,600 km (500 to 1,000 miles) from the breeding colony. It is not known if all the birds from one colony migrate to the same over-winter zone.

Many adults across the Strait of Gibraltar in the west of the Mediterranean and fly over land as much as possible. Other birds follow Africa's Atlantic coast to reach the Gulf of Guinea.

The northernmost gannets that fly from the colonies of Canada fly much further south than the adults into the Gulf of Mexico. Immature janitors migrate south for great distances and are recorded as far south as Ecuador.

In their second year, some birds return to their birth colony, where they come later than mature birds. They then migrated south after the breeding season but traveled a short distance on this second migration.

Alderney's Gannet have been tracked for over 20 years to gain a better understanding of their movements.

One was seen traveling from his colony to Alderney to the waters of Scandinavia, traveling about 2,700 km (1,680 miles) round.

The species has been recorded as the Black Sea in many central and eastern European countries in the south and west, and in Bermuda, Cuba, Cyprus, Egypt, Kazakhstan, Jan Mayen, and several Central and Eastern European countries.

On February 26, a record was made from Kerry, northeast Brazil - the first seen in the southern hemisphere.

Behavior

The wings of the North Gannet is long and narrow and located at the front of the body, giving the aircraft the efficient use of air currents while flying.

Even in calm weather, they can achieve speeds of 55 to 65 km / h (34 and 40 mph) although their flying muscles are relatively small: the flying muscles in other birds are about 20% of the total weight, while the flying muscles in North Gannett are at least 13%.

Despite their speed, they are not able to operate other marine rocks along with the flight. Northern gannets need to be warmed up before flying so they can walk with difficulty and that means they have trouble getting air out of a plane.

They face the wind and forcefully lower their wings and lower them from the water. In light winds and high waves, they are sometimes unable to move and maybe beached.

The Gannet stands on the ground using angular wings, fantail and raised legs to control their motion since damaged or broken wings are not often recorded as the cause of death in adults in a colony.

Upbringing

Northern Gannet for daytime snacks, usually submerged at high speeds in the sea তারা They search for both foods near their nest sites but also out to sea. The bird that feeds the baby has been found 320 km (200 miles) away from home.

It was found that 2% of the birds were nesting in the colony of the tiger rock at Dugger Bank, 25 to 120 km (9 and 9 and 20 miles) in search of fish.

They may have flown more than this when foraging, perhaps doubling in the distance; Usually, they fly less than 150 kilometers (93 miles).

Some studies have shown that the duration and direction of planes when feeding is similar for both sexes, although there are significant differences between males and females in search behavior.

Female northern gannets are not only more desirable than men in choosing the search zone: they take longer and deeper dives and spend more time floating on the surface than men.

The Gannet will follow fishing boats or cetaceans to find abandoned or injured fish. They graze from a height of 70 meters (230 feet) with no clear choice and usually sink 11-60 meters (36-197 feet).

They dip their bodies straight and hard, the wings are close to the body but back to the corners, extending beyond the tail, before spraying water like an arrow.

They control the right side of the wings, use their wings and tail and fold their wings against the body just before impact. Birds can hit the water at speeds of up to 100 km / h (62 miles).

This allows them to penetrate up to 11 meters (36 feet) below the surface, and they will swim on average 19.7 meters (60 feet), sometimes deeper than 25 meters (80 feet). The subcutaneous air sacs of the birds may play a role in controlling the ejaculation.

The Gannet usually push their prey deeper into the water and capture it as they return to the surface. If a dive is successful, they swallow the water submerged before surfacing and do not fly with the fish in their bill.

Big fish are swallowed headfirst, small fish are swallowed side by side or tail-first. The fish is stored in a branched bag in the neck and cannot be pulled while the aircraft is moving.

Their white color helps other janitors to identify one of their kind, and they can reduce the appearance of the fish's sheath through this diving behavior; This, in turn, facilitates teaming foraging which makes it easier to catch their prey.

The color makes Gannet less visible on the bottom fish. Northern janitors also forage for fish by swimming with their heads in the bottom of the head.

They feed mainly 2.5-30 mm (1-12 inches) of shoal length near the surface of the surface. Virtually any small fish (about 3-5% of their diet) or other small pelagic species (mainly squid) will be taken advantageously. Sardines, anchovies, haddock, molten, Atlantic cod and other shoal-forming species are eaten.

Breeding

The oldest birds first returned to the breeding colony of Northern Gannet. Birds that are not of reproductive age arrive a few weeks later.

Normally, when the birds first return to a colony when they are two years old (not the way they were dispersed), they usually do not change to another once a person is successfully born in a colony. Nesting begins in March or April.

The immature bird lives on the edge of the colony. They can even build nests but do not breed until they are four or five years old. Some birds of this age occupy an empty nest that will aggressively protect them if they are sitting for two or three days.

If the owner of an apparently empty nest is found, the immature bird will leave without a fight when the owner arrives to occupy it.

Preferred nesting sites are at the summit or summit of the coastal mountains. If these are not available, northern gannets will nest in groups of islands or flat surfaces.

As they find it more difficult to travel from such locations, they often generate an aggressive response from the thrust of settling the area occupied by the surrounding nest; This means that the pressure level is higher in this type of colony than on the steeper surfaces.

Nevertheless, nests are always built close together, and otherwise, ideal nesting sites will not be used if they are somewhat away from a colony. On average, there are 2.3 dwellings per square meter (1.9 per square meter).

Both sexes severely protect the area surrounding their nest. Where space allows, the distance between nests is twice the reach of a person.

The nests are made from marine reservoirs, plants, debris from the earth and the sea. Men usually collect materials. The nest's compact cups are usually 30-60 cm (12-24 in) in height.

The area occupying a nest grows throughout the breeding season as breeding joints move out of the nest, year after year, nests can reach 2 m (7 ft) in height.

The northern gannets give an egg which on average weighs 104.5 grams (3.7 oz), which is light for such a large marine bird. The egg is about 5 mm (2.5 inches) wide in length, about 5 mm (1.7 inches) long, and the shell is initially pale blue and transparent, before fading to a glossy white surface.

Where two eggs are found in one nest, it is either two females laying an egg in the same nest or one egg being stolen from another nest.

If the first one is lost, the northern gannets will get a replacement egg. Incubation takes 42 to 46 days, during which time the egg brooding is surrounded by the warm, webbed legs of the bird.

Just before the baby starts to hatch, the bird lays its eggs from the egg's eggs so that the egg can not bend under the weight of the adult as soon as it is opened. This is a frequent cause of first-time reproductive death for bird rats.

The process of breaking the ovary can take up to 36 hours. Incognito legs are used to cover the rails, which are rarely left by their parents alone. The rats that are left unchanged are often attacked and killed by other northern janitors.

The new burnt pellets are featherless and are dark blue or black. In the second week of life, they are covered with white bottom, replaced by dark brown feathers with white color over the next five weeks.

Babies are fed to their spiritual half-digested fish, who spread their babies' mouths to bring food from the back of their throats.

Old raft gets whole fish. Unlike other species of rats, northern Gannet rats do not wander about the nest or rush to ask the wings: it reduces the chances of falling from the nest.

Adults feed their offspring for about 13 weeks until their feeding time. Young birds are promised within 88 to 97 days that they themselves begin to fly from an opening and fly - a process that is impossible to practice before.

If they leave the nest in bad weather, they may be seriously injured because they can fly against the rocks.

Young birds are attacked by birds if they are not large. Once they leave the nest, they stay near the sea to learn to fish and fly, unable to reach their line of descent because of their poor flying ability.

Predators and parasites

The Gannet of the North is not very predictable. The only known habitual natural predators in adults are tuck ag gall and white tail gull.

Egg and nest predators include the great black-backed gull and the American herring gull, the common crow, the Eriman, and the red fox. Sea attacks are trivial, though large sharks and seals can rarely snatch Gannet towards the sea.

Kleptoparasitism by squua, especially in the great squua breeding place. By providing food to the attacker, Scuia pursues his victim until he sprinkles the contents of his stomach.

The skew can catch the jaunt's wings, fall into the sea, or seize the tail to submerge its prey in the water. Gannet is only released when it has reorganized its catch.

Exotic parasites include feather lice, although there are relatively few species and none are found in the head. Like grubs and divers, it could also be that smaller feathers provide insufficient cover for the parasite.

In one species Michaelchus resident, immature lice are found on the membranes lining the air-cells beneath the screen. Icodus mites include a wide range of urea.

In Corynosoma tunaite, the prickly-headed worm is seen only in gannets and closely related marine families such as cormorants.

Tapeworm tetrobothrias accumulates toxic heavy metals at higher densities than the resident gant's own tissues, an average of 12 times higher than Gannet's pectoral muscles and 7-10 times the lead levels of the kidney and liver of birds.

Because the levels of these toxic metals are detectable in the parasite compared to the host, the tapeworm can be used as a primary indicator of marine contamination.

Conservation status

Nest in the rocks. The population of this species seems to be increasing.

A 2004 survey counted 45 Gannet breeding colonies and about 361,000 homes. The population is obviously growing between 3% and 5% a year, although this growth is concentrated in only a few colonies.

Although the population of North Gannet is now stable, their numbers have declined at once due to habitat loss, egg removal and killing of adults for meat and feathers.

In 1939, there were 22 colonies and about 83,000 dwellings, meaning that the population had increased fourfold since that time.

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