Bird Families

Razorbill or lesser auk (Alca torda) Overview and facts

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Razorbill or lesser auk (Alca torda) is a colonic marine bird of the genus Alcida, a genus of alcidi of the Aus family. It is the closest living relative of the extinct Great Auk (Pinguinis empenis). Wild populations live in the subarctic waters of the Atlantic Ocean.

Razorbill auk is essentially black with a white underside. Men and women alike in the plumage; However, a male razor billed auk is usually larger than females These clever birds, which are capable of both aircraft and diving, have a predominantly aquatic lifestyle and are simply landed for breeding. It is exclusive, choosing a partner for life.

The female Razorbill or lesser auk (Alca torda) lays one egg per year. Razorbills nest along coastal waters in enclosed or slightly exposed crevices. Parents spend an equal amount of time incubating, and after the rooftop is thrown, they turn around for their kids.

In 1918, the Razorbill was protected by the United States Migratory Bird Treaty Act. Currently, the biggest threat to the population is the destruction of the breeding site.

Description

During the breeding season, Razorbill or lesser auk (Alca torda) has white underparts and a black head, neck, back, and legs. A thin white line also extends from the eye to the end of the bill. Its head is darker than a normal bend. During the breeding season, the neck and face of the eyes become white and the white line of the face becomes less prominent.

The dense black bill has a blunt end. It is large for an alcide and has an average weight of 505 to 890 grams (17.8 to 31.4 oz). There are only small differences between the wings and lengths of females and males in very adult males.

This species has a horizontal position, and the tail feathers are somewhat longer in the middle than other alcids. This puts an obvious long tail on the razorbill that is not common to the auk. There are discussions about guillemot and razorbill.

Their conjugal system of the Razorbill or lesser auk (Alca torda) is a single marriage by a female implementer; Razorbill chooses a partner for life. It nestles open or hidden between cliffs and boulders. It is a colonial breeder and simply descends on the breed. The annual survival rate of the razorbill is between 89-95%.

Although the average life expectancy of razorbill is about 13 years, in the United Kingdom in 1967, a winged bird survived for at least five years. This is a record for the species.

Distribution and Accommodation

Razorbills are distributed throughout the North Atlantic; The global population of the razorbill is estimated to have fewer than a thousand breeds, making it the lowest number in the world. About half of the breeding pairs occur in Iceland, with razorbills succeeding at water surface temperatures below 15 ° C.

They are often seen with other larger auks, such as thick-billed twigs and common kuria, but they generally move to larger estuaries with lower salinity levels to feed compared to other auks. These birds are distributed throughout the sub-Arctic and boreal waters of the Atlantic. Their breeding habitats are the islands, rocky shores and mountains on the North Atlantic coast, south of Maine in eastern North America, and in western Europe, from northwest Russia to northern France.

North American birds migrate offshore and south, from the Labrador Sea in the south to the Grand Banks of Newfoundland to New England. Eurasian birds also extend south to the western Mediterranean in the winter of the sea. In Iceland, approximately 60 to 70% of the entire reserve population is bred.

The Razorbill colonies include (north to south):

  • Gramsci, Iceland (66 ° 33 'N)
  • Latabourg, Iceland (65 ° 30 'N) - 230,000 pairs, about 40% of the world population (estimated in the mid-1990s). Breeding season June - July
  • Rwanda, Norway (62 ° 24 'N) - 3,000 pairs
  • Staple Island, Outer Fern Islands, United Kingdom (55 ° 38 'N) - 20,000 pairs, breeding season from May to July.
  • Bempton Cliffs, [Flamborough and Filey Coast Special Protection Area] United Kingdom (54 ° 14 'N) - 20,000 yachts from mid-March to mid-July.
  • Heligoland, Germany (54 ° 10 'N) - Only a few pairs, close to the southern boundary of Europe
  • Gannett Islands, Canada (53 ° 58 'N) - 9,800 Pairs
  • Funk Island, Canada (49 ° 45 'N)
  • Bacalieu Island, Canada (48 ° 07 'N)
  • Witless Bay, Canada (47 ° 13 'N)
  • Cape St. Mary, Canada (46 ° 49 'N)

Behavior

The life-history features of the Razorbills are in line with that of the common twist. However, the Razorbill or lesser auk (Alca torda) is a bit more sticky. During breeding, both males and females protect the nest. Women choose their mates and often encourage competition among men before choosing a mate. Once a male is selected, the pair will be together for the rest of their lives.

Reproduction

Individuals only breed at 3-5 years of age. As the pair grows, they will sometimes skip a year of breeding. A mating pair will court several times during the breeding period to strengthen their bond. Courtship displays include touching bills and following each other in a wide variety of aircraft types.

When the pre-emptive period begins, men will regularly defend their mates by throwing other men with the bill. This pair will meet 80 times over a 30 day period to ensure drainage. Women will sometimes encourage other men to engage in genitalia to guarantee successful fantasy.

During the pre-ovarian period, the Razorbills will socialize greatly. There are two types of socialization that occur. Large parties will sink repeatedly into circles together, and all will rise above the surface and the bills open. Secondly, the big teams will swim in a line of knitting across each other on the same side.

Nest site

Nest site determination is very important for these birds in order to ensure the protection of children from predators. In contrast to the murders, the nest sites are located not immediately along the steep canal of the opening but at least 10 cm (3.9 inches) away, in the middle of the cliffs or rocks. The nests are usually enclosed in rock or slightly more open. Some sites are along the creek, but the Crevice sites appear to be more successful as they reduce prediction.

Confluence pairs will often reuse the same site every year. When leaving the colony, the goats do not have the ability to fly home near the sea. Generally, razorbills do not build nests; But some pairs often use bills to pull the ingredients in to give them eggs.

Incubation and hatching

The female lays one egg per year. The egg has an ovary-pyramidal shape, ground color, and dark brown spots. Egg-laying usually takes 48 hours after incubation. Females and males hatch eggs about several times a day, before hatching.

Razorbill wheels are semi-precision. In the first two days afterburn, the rash will spend most of its time under the wings of the parents. There is always one parent at the nest site while the other goes to the sea to collect goat food. Hatchling develops a complete shea 10 days after hatching. After 3-20 days, the male father will take the baby to the sea.

Upbringing

The Razorbills dive deep into the sea with their wings and flowing bodies to drive them to prey. When diving, they are rarely in the group but spread out to feed them. Most of their feeding occurs at depths of 25 meters (82 feet) but they have the ability to sink to 120 meters (390 feet) below the surface. When giving a single dive, a person can capture and consume much school-based fish, depending on their size. Razorbills spend about 44% of their time slowly in the ocean.

When feeding their babies, they usually provide small loads. Adults usually feed only one fish on their chickens, delivering high feed distribution at dawn and 4 hours before dark. Females usually feed their babies more frequently than males. Eggs can fly up to 5 km (mi 2 mi) to sea for feeding, but they are close to the nesting ground, about 12 km (7.5 mi) away and often in shallow water when feeding the young.

Diet

The diet of razorbill is very similar to that of a simple twist. It is usually composed of mid-water school fish such as capelins, sand lenses, juvenile cod, sprouts, and herring. It may also include crustaceans and polychaetes. A recent study found that the diet of the razorbill influences the local and regional environmental conditions of the marine environment.

Predators

The adult razorbill has a number of predators including a polar bear, great black-backed gulls, peregrine falcon, crow, crow, and jackdaw. The common predators of their eggs are roses and crows. Diving is the best opportunity for adult razorbills to avoid predation. Arctic foxes can also predict a significant number of adults, eggs, and rats within a few years.

Conservation and management

In the early 20th century, razorbill was collected for eggs, meat, and feathers. It has reduced the global population. In 1717 they were eventually protected by the “Migratory Bird Contract Act” which reduced hunting. Other threatening interactions include oil pollution that can damage breeding sites.

Any loss of breeding sites could potentially reduce nest sites and affect the breeding of species. Commercial phishing has an impact on the population because razorbills can be tied into nets. Overfishing reduces the abundance of razorbills and thus affects their survival

Watch the video: PARROT CLEANING HIS FEATHER (March 2021).

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