4 عدد تمبر پرندگان دریائی حفاظت شده - جمهوری فدرال آلمان 1991

philomachus pugnax, sterna albifrons, branta bernicla, haliaeetus albicilla

توجه : درج کد پستی و شماره تلفن همراه و ثابت جهت ارسال مرسوله الزامیست .

توجه:حداقل ارزش بسته سفارش شده بدون هزینه پستی می بایست 100000 ریال باشد .

The ruff (Philomachus pugnax) is a medium-sized wading bird that breeds in marshes and wet meadows across northern Eurasia. This highly gregarious sandpiper is migratory and sometimes forms huge flocks in its winter grounds, which include southern and western Europe, Africa, southern Asia and Australia. It is usually considered to be the only member of its genus, and the broad-billed and sharp-tailed sandpipers are its closest relatives.

The ruff is a long-necked, pot-bellied bird. This species shows marked sexual dimorphism; the male is much larger than the female (the reeve), and has a breeding plumage that includes brightly coloured head tufts, bare orange facial skin, extensive black on the breast, and the large collar of ornamental feathers that inspired this bird's English name. The female and the non-breeding male have grey-brown upperparts and mainly white underparts. Three differently plumaged types of male, including a rare form that mimics the female, use a variety of strategies to obtain mating opportunities at a lek, and the colourful head and neck feathers are erected as part of the elaborate main courting display. The female has one brood per year and lays four eggs in a well-hidden ground nest, incubating the eggs and rearing the chicks, which are mobile soon after hatching, on her own. Predators of wader chicks and eggs include mammals such as foxes, feral cats and stoats, and birds such as large gulls, corvids and skuas.

The ruff forages in wet grassland and soft mud, probing or searching by sight for edible items. It primarily feeds on insects, especially in the breeding season, but it will consume plant material, including rice and maize, on migration and in winter. Classified as "least concern" on the IUCN Red List criteria, the global conservation concerns are relatively low because of the large numbers that breed in Scandinavia and the Arctic. However, the range in much of Europe is contracting because of land drainage, increased fertiliser use, the loss of mown or grazed breeding sites, and over-hunting. This decline has seen it listed in the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).

The little tern (Sternula albifrons or Sterna albifrons) is a seabird of the tern family Sternidae. It was formerly placed into the genus Sterna, which now is restricted to the large white terns.^[3] The former North American (S. a. antillarum) and Red Sea S. a. saundersi subspecies are now considered to be separate species, the least tern (Sternula antillarum) and Saunders's tern (Sternula saundersi).

This bird breeds on the coasts and inland waterways of temperate and tropical Europe and Asia. It is strongly migratory, wintering in the subtropical and tropical oceans as far south as South Africa and Australia.

There are three subspecies, the nominate albifrons occurring in Europe to North Africa and western Asia; guineae of western and central Africa; and sinensis of East Asia and the north and east coasts of Australia.^[4]

The little tern breeds in colonies on gravel or shingle coasts and islands. It lays two to four eggs on the ground. Like all white terns, it is defensive of its nest and young and will attack intruders.

Like most other white terns, the little tern feeds by plunge-diving for fish, usually from saline environments. The offering of fish by the male to the female is part of the courtship display.

This is a small tern, 21–25 cm long with a 41–47 cm wingspan. It is not likely to be confused with other species, apart from fairy tern and Saunders's tern, because of its size and white forehead in breeding plumage. Its thin sharp bill is yellow with a black tip and its legs are also yellow. In winter, the forehead is more extensively white, the bill is black and the legs duller. The call is a loud and distinctive creaking noise.

Populations on European rivers

At the beginning of the 19th century the little tern was a common bird of European shores, rivers and wetlands, but in the 20th century populations of coastal areas decreased because of habitat loss, pollution and human disturbance.

The loss of inland populations has been even more severe, since due to dams, river regulation and sediment extraction it has lost most of its former habitats. The Little Tern population has declined or become extinct in many European countries, and former breeding places on large rivers like the Danube, Elbe and Rhine ceased. Nowadays, only few river systems in Europe possess suitable habitats; the Loire/Allier in France, the Vistula/Odra in Poland, the Po/Ticino in Italy, the Daugava in Latvia, the Nemunas in Lithuania, the Sava in Croatia and the Drava in Hungary and Croatia. The status of the little tern on the rivers Tagus and lower Danube is uncertain.

The Drava population is one of the most threatened. Old fashioned water management practices, including river regulation and sediment extraction, endanger the remaining pairs. Only 15 pairs still breed on extensive sand or gravel banks along the border between Hungary and Croatia. The WWF and its partners are involved in working for the protection of this bird and this unique European river ecosystem. The little tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

The brant or brent goose (Branta bernicla) is a species of goose of the genus Branta. The black brant is an American subspecies. The specific descriptor bernicla is from the same source as "barnacle" in barnacle goose, which looks similar but is not a close relation. The Brent Crude, a major trading classification of sweet light crude oil that serves as a major benchmark price for purchases of oil, was named after the species.^[2]

The white-tailed eagle (Haliaeetus albicilla^[2]) — also called the sea eagle, erne (sometimes ern, ørn), and white-tailed sea-eagle — is a large bird of prey in the family Accipitridae which includes other raptors such as hawks, kites, and harriers. It is considered a close cousin of the bald eagle and occupies the same ecological niche, but in Eurasia.

Description

The white-tailed eagle is a very large bird. It measures 66–94 cm (26–37 in) in length with a 1.78–2.45 m (5.8–8.0 ft) wingspan. The wingspan, with a midpoint of 2.18 m (7.2 ft), is on average the largest of any eagle.^[3][4] The Steller's sea eagle, larger in both weight and total length, is the closest rival for median wingspan amongst living eagles.^[3] The bald eagle is roughly the same size as the white-tailed eagle, although has a shorter average wingspan and usually longer total length, due to a longer tail.^[3] Females, typically weighing 4–6.9 kg (8.8–15.2 lb), are slightly larger than males, which weigh 3.1–5.4 kg (6.8–11.9 lb)n^[3] The record weight for the species was 7.5 kg (17 lb) for a specimen from Scotland, while a more recent huge female from Greenland reportedly spanned 2.53 m (8.3 ft) across the wings.^[5][6] Among standard measurements, the wing chord is 55.2–71.7 cm (21.7–28.2 in), the tail is 25–33 cm (9.8–13.0 in), the tarsus is 9.2–10.1 cm (3.6–4.0 in) and the exposed culmen is 6–6.5 cm (2.4–2.6 in).^[3][7] Size variation is generally a clinal trend: measurements of eagles from Greenland are in general larger than in other populations of the species, while those from the (now discontinuous) population in the Middle East, at the southern extreme of this species distribution, are the smallest in the species.^[3][8] The white-tailed eagle is sometimes considered the fourth largest eagle in the world ^[9] and is on average the fourth heaviest eagle in the world.^[3][10]

This species has broad "barn door" wings, a large head and a large thick beak. The adult is mainly grayish-brown except for the slightly paler head and neck, blackish flight feathers, and distinctive white tail. All bare parts are yellow in color, including both the bill and the legs. In juvenile birds, tail and bill are darker, the tail becoming white with a dark terminal band in sub-adults.^{[11][page needed]} The combination of mousy-brown coloration, broad, evenly held wings, white tail, strong yellow bill and overall large size render the white-tailed eagle essentially unmistakable in its native range.^[3]

Some individuals have been found to live over 25 years,^[12] 21 years being the average.^[9]

Distribution and systematics

This large eagle breeds in northern Europe and northern Asia. The largest population in Europe is found along the coast of Norway. The population in 2008 stood at only 9,000–11,000 pairs.^[9] They are mostly resident, only the northernmost birds such as the eastern Scandinavian and Siberian population migrating south in winter. Birds from eastern Russia rarely migrate into Alaska.

Small disjunct resident populations occur in southwesternmost Greenland and western Iceland. The former has been proposed as a distinct subspecies, groenlandicus, based on their very large size and body proportions. However, the species is now considered monotypic and the size variation is clinal according to Bergmann's rule.^{[13][page needed]} A recent genetic study of mitochondrial DNA^[14] is consistent with this idea. Greenlandic white-tailed eagles form, on evolutionary time scales, a relatively recently founded population that has not yet accumulated many unique genetic characteristics. However, the population appears to be demographically isolated and deserves special protection.

The white-tailed eagle forms a species pair with the bald eagle. These diverged from other sea eagles at the beginning of the early Miocene (c. 10 mya) at the latest, possibly (if the most ancient fossil record is correctly assigned to this genus) as early as the early or middle Oligocene, about 28 mya.^[15]

As in other sea-eagle species pairs, this one consists of a white-headed (the bald eagle) and a tan-headed species. They probably diverged in the North Pacific, spreading westwards into Eurasia and eastwards into North America. Like the third large northern species, Steller's sea eagle, adults have yellow feet, beaks and eyes.

Currently, eagles only occur in the Hawaiian Islands as vagrants, but Quaternary bones of Haliaeetus have been found on three of the major islands. An ancient DNA study published in 2015 in Molecular Phylogenetics and Evolution characterized the rapidly evolving mitochondrial control region of one of these specimens.^[16] The authors analyzed DNA from a ∼3500-year-old sea eagle skeleton found in a lava cave on the island of Maui, Hawaii. Phylogenetic analyses suggested that the Hawaiian eagle represents a distinct (>3% divergent) mtDNA lineage that is most closely related to extant White-tailed Eagles. Based on fossil calibration, the authors estimated that the Hawaiian mtDNA lineage diverged around the Middle Pleistocene. Thus, although not clearly differentiated in its morphology from its relatives, the Hawaiian eagle likely represented an isolated, resident population in the Hawaiian archipelago for more than 100,000 years, where it was the largest terrestrial predator. The reasons for its extinction are unknown at this point.

Diet

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The white-tailed eagle's diet is varied, opportunistic and seasonal. Prey specimens can often include fish, birds and mammals. Many birds live largely as scavengers, regularly pirating food from otters and other birds including cormorants, gulls, ospreys and various other raptors.^[3] Carrion is often the primary food source during lean winter months, with fish and ungulates preferred but everything from cetaceans to livestock to even humans being eaten after death.^[3][17] Among the scavengers in their range, eagles are often dominant over all but perhaps the largest carnivorous mammals (i.e. gray wolves, etc.)^[3] However, this eagle can be a powerful hunter as well. In Scotland the diet of this species differs significantly from that of sympatric golden eagles, as is also the case in Norway.^[3] The daily food requirement for a white-tailed eagle is in range of 500–600 g (1.1–1.3 lb).^{[18][page needed]} Although generally a less active hunter than the golden eagle, competition over food can go either way depending on the individual eagle. They can exist at higher population densities and typically outnumber golden eagles because of their longer gut and more efficient digestive system, being able to live better with less food.^[19]

Virtually any fish found near the surface is potential prey for the white-tailed eagle.^[3] Commercial fisheries and carp ponds are readily exploited by the eagles when available.^[3] Although, given the opportunity, they occasionally kill and harass some land birds, white-tailed eagles usually target water-based birds as prey.^[3] In the Baltic the diet of this species consists mainly of sea birds (from the little tern to the great skua) and pike. Recently they are reported to have attacked and eaten great cormorants and in some cases destroyed whole colonies.^[20] In the Estonian island of Hiiumaa, home to at least 25 pair of sea eagles, as many as 26 individuals have been observed simultaneously culling a single cormorant colony.^[21] In the UK, fulmar are noted as a common prey species and as such may contribute to locally high levels of DDT and PCB chemicals in nesting eagles.^[17] Additionally, loons, grebes, ducks, coots, auks, gulls, geese and even swans have been preyed upon.^[3] Adults, nestlings and eggs of other birds are all regularly consumed. When preying upon non-nesting birds, white-tailed eagles often fly towards a waterbird repeatedly, forcing it to dive again and again until the bird is exhausted and more easily caught.^[3] Very large prey such as swans may be dragged along the surface of the water to the shore to be consumed.^[3] Live mammals consumed have ranged in size from voles to lambs and deer calves, the latter likely around the same size as the record-sized deer carried by bald eagles in North America.^[3]

Breeding

White-tailed eagles are sexually mature at four to five years of age. They pair for life, though if one dies replacement can occur quickly. A bond is formed when a permanent home range is chosen. They have a characteristic aerial courtship display which culminates in the pair locking talons mid-air and whirling earthwards in series of spectacular cartwheels. White-tailed eagles are much more vocal than golden eagles, particularly during the breeding season and especially the male when near the eyrie. Calls can sometimes take the form of a duet between the pair.

The nest is a huge edifice of sticks in a tree or on a coastal cliff. Being faithful to their territories, once they breed, nests are often reused, sometimes for decades by successive generations of birds; one nest in Iceland has been in use for over 150 years.^{[11][page needed]} In Scandinavia, trees have been known to collapse under the weight of enormous, long-established nests.

The territory of the white-tailed eagle ranges between 30 and 70 km², normally in sheltered coastal locations. Sometimes they are found inland by lakes and along rivers. Territory of white-tailed eagles can overlap with those of the golden eagle but competition between the two species is limited. Golden eagles prefer mountains and moorland, while the white-tailed eagle prefers the coast and the sea. In adulthood the white-tailed eagle has no natural predators and is thus considered an apex predator.

Mated pairs produce one to three eggs per year, laid two to five days apart in March or April and incubated for 38 days by both parents. Once hatched, chicks are quite tolerant of one another, although the first hatched is often larger and dominates at feeding times. The female does most of the brooding and direct feeding, with the male taking over now and then. Young are able to feed themselves from five to six weeks and they fledge at eleven to twelve weeks, remaining in the vicinity of the nest, dependent on their parents for a further six to ten weeks. The sex of nestlings can be identified using field methods, or using DNA.^[22]

Surplus chicks are sometimes removed from nests to use in reintroduction programs in areas where the species has died out. If left in the nest, they often die sooner or later, as with most large eagles. In such programs the birds are raised in boxes on platforms in the tree canopy and fed in such a way that they cannot see the human supplying their food, until they are old enough to fly and thus find their own food.