Osprey

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Osprey
Approaching osprey in Mecklenburg

Approaching osprey in Mecklenburg

Systematics
Class : Birds (aves)
Order : Birds of prey (Accipitriformes)
Family : Osprey
Genre : Osprey
Type : Osprey
Scientific name of the  family
Pandionidae
Sclater & Salvin , 1873
Scientific name of the  genus
Pandion
Savigny , 1809
Scientific name of the  species
Pandion haliaetus
( Linnaeus , 1758)

The osprey ( Pandion haliaetus ) is a species of bird from the order of the birds of prey (Accipitriformes). Due to numerous special characteristics, the species is usually placed in its own family Pandionidae , this family and the genus Pandion are thus monotypical . The species is distributed almost worldwide and is also found in Central Europe.

description

Ospreys are medium-sized, slender and long-winged birds of prey. The body length is 50 to 66 cm, the wingspan is 1.27 to 1.74 m. Females are on average larger and heavier than males. Females of the nominate form P. h. haliaetus have a wing length of 470 to 518 mm and a weight of 1.21 to 2.05 kg, males reach a wing length of 448 to 495 mm and a weight of 1.12 to 1.74 kg.

In adult birds of the nominate form , the back and upper side of the wings are monochrome dark brown, only the tail is drawn light-dark on the upper side and shows a broad, dark end band. The underside of the entire trunk, throat, legs, and most of the forearm covers are bright white. The breast shows a brownish band that is usually much wider and darker in females than in males. Otherwise, the sexes show no differences in color or markings. The undersides of the wings and tail are densely banded dark on a whitish background. The large forearm coverts are blackish and therefore form a clear contrast to the otherwise white under wing coverts and to the wings. The underhand covers are also blackish and therefore form a clearly visible dark spot on the bend of the wing.

The white head shows a broad, sharply defined, dark brown eye stripe that extends from the base of the beak to the neck. The wax skin and the base of the beak are lead gray, the rest of the beak is black. The featherless parts of the legs are pale blue-gray, the claws are black. The iris is yellow.

In the youth dress , all cover feathers on the upper side have a light border, so that the upper side appears clearly scaled overall. The large forearm coverts are banded light-dark and not monochrome dark, so that they hardly contrast with the rest of the wing underside. The white top of the head is clearly darkly striped, which means that the head drawing is less contrasty overall. In contrast to adult eagles, juveniles have an orange iris. After the first moult, the young birds are colored.

In flight, ospreys look remarkably long and narrow-winged. Very often the hand wing is bent slightly downwards in the wrist, so that the bird looks like a large seagull from a distance .

In adaptation to its highly specialized diet, the osprey shows numerous special characteristics. So the nostrils are slanted and slit-shaped. Ospreys have no trousers , so no long, drooping lower leg fletching, and the very powerful tarsometatarsus is feathered except for the uppermost part. The short but very strong toes have many small, thorn-like pointed scales on the underside, the outer (third) toe can be turned backwards. The claws are very long and pointed and very strongly curved; they are oval in cross-section and not, as in almost all other birds of prey, concave on the underside . As a further specialty, the down plumage of the osprey is not in feather corridors .

Vocalizations

The male's courtship call is a long-range, two-syllable, rather whistling "ü-iilp". If the nest is disturbed, the adult birds call “kju-kju-kju” in a row. When conspecifics fly to the nest of a couple, the territorial birds call piercingly and also rather whistling "pjüpp".

distribution and habitat

Distribution of the osprey:
  • Breeding areas
  • Year-round occurrence
  • migration
  • Wintering areas

    • The osprey is found almost all over the world. The breeding area includes the boreal to subtropical zones of the Holarctic , parts of the Caribbean , the tropics of Southeast Asia and Australia .

    In Europe , the distribution of the species is largely fragmented due to intensive human persecution until the mid-1950s and is mainly limited to the north and east. In western Europe the osprey breeds only in Scotland and more recently in central France and Wales . In Central Europe the species occurs only in Germany and Poland, in Germany the distribution is largely limited to the new federal states. Large populations have been able to hold in Scandinavia .

    The huge range of the osprey is primarily due to its comparatively low habitat requirements; they are essentially limited to fish-rich, slow-flowing or stagnant waters and neighboring breeding opportunities in the form of trees, rock faces, artificial structures or uninhabited and predatory mammal-free islands.

    Systematics

    More recent molecular genetic studies have also confirmed the special position of the osprey within the order of birds of prey; it is usually placed in its own family Pandionidae, occasionally only in a subfamily within the family Accipitridae.

    In addition to the nominate form, three subspecies are currently distinguished:

    • P. h. haliaetus : Entire Palearctic
    • P. h. carolinensis : North America to the south to the Gulf of Mexico , somewhat larger in comparison to the nominate form, almost pure white above the eyes, largely absent chest mark, darker brown on the upper side.
    • P. h. ridgwayi : Caribbean ( Bahamas , islands off Cuba , Yucatan , Belize ); smaller than the nominate shape, the stripes above the eyes are even whiter and the chest mark is even more reduced than in P. h. carolinensis .
    • P. h. cristatus : From Sulawesi and Java to the east to the Solomon Islands and New Caledonia , coasts of Australia. Smaller and more short-winged than the nominate form, the white over-eye stripe wider and extended to the nape of the neck, so that the eye stripe is not associated with the dark color of the neck.

    In a molecular genetic investigation of three of the four subspecies ( P. h. Haliaetus , P. h. Carolinensis and P. h. Cristatus ), genetic distances of two to four percent were found, which could justify a species status for each of these subspecies.

    Hunting style and diet

    Osprey ( Pandion haliaetus ) with prey
    Almost full-fledged osprey in the eyrie

    Without exception, the hunt takes place in and over water. It is not uncommon for fish to be sought from a viewing point on the bank, but more often from a low circle at a height of 10 to 30 meters above the water surface. When a suitable fish is discovered, the eagle shakes the spot and then thrusts into the water with its feet outstretched. The dive can take place vertically, but also at any other angle to the water surface; in shallow waters the impact is often almost parallel to the water surface. When trying to hunt, the osprey usually lands briefly in the water, then takes off again after a few seconds with a few strong flaps of its wings, circles briefly and then shakes the water out of its plumage in flight. If the hunt is successful, the eagle will grab a larger fish and transport it head first to the nest or to a feeding site. Most fish eat only the head and front part of the body, the rest is often dropped.

    The food consists almost exclusively of small to medium-sized, mostly 100 to 300 g heavy sea and freshwater fish. These are usually captured alive, only occasionally dead fish are used. Other animals that are mostly bound to water, such as small mammals, injured or weakened birds, small turtles and crocodiles , frogs and crabs are rare chance or opportunity prey .

    Reproduction

    Egg, Museum Wiesbaden collection

    Ospreys are usually sexually mature in the third calendar year, i.e. at the age of almost two years, and can then breed. They lead a monogamous seasonal marriage, the loyalty to the breeding site often leads to re-breeding of the partners from the previous year.

    Ospreys usually breed individually, but often also in loose colonies, with only the immediate nesting area being defended. Depending on the natural conditions, the nest is built on trees, on rock walls or on the ground, in Central Europe and North America also very often on artificial structures, especially on power poles. It is normally exposed upwards and can be approached freely. Ospreys build large nests out of strong and mostly dead branches, the nesting hollow is padded with grass. The clutch usually comprises two to three, rarely only one or four eggs , which are spotted intensely reddish-brown on a white background and are incubated for 38 to 41 days. After another 50 to 54 days, the young birds are fledged.

    hikes

    Depending on the geographical location, the osprey is a resident or long-distance migrant . The breeding birds of the Holarctic are almost without exception long-distance migrants; the North American ospreys overwinter in South America, the Eurasian birds occasionally overwinter in the Mediterranean area, but mostly in Africa south of the Sahara and in South and Southeast Asia. The breeding birds of the southern tip of Florida , the Caribbean , the Mediterranean, the Arabian Peninsula, Southeast Asia and Australia are predominantly resident birds or only pass over short distances in winter.

    The osprey is not dependent on thermals for its migrations and, as a broad-fronted migrant, crosses seas and deserts even at their widest points. There are therefore no noticeable draft concentrations at the land bridges or bottlenecks such as the Bosporus or Gibraltar , as are typical for thermal migrants .

    In Central Europe, ospreys migrate from the breeding areas from August, the last migrants are observed here around mid-November. The eagles return to the breeding grounds from the end of March to mid-April.

    Existence and endangerment

    Osprey in Mecklenburg

    By the mid-1950s, the osprey had been wiped out through human persecution in much of Europe and North America. The species suffered further population losses in the 1950s to 1970s due to polychlorinated biphenyls and the insecticide dichlorodiphenyltrichloroethane (DDT), which accumulates particularly strongly in aquatic food chains and inhibited or prevented the reproduction of the osprey. Since the ban on DDT in Europe and North America in the early 1970s, stocks here have recovered significantly and are still increasing in many regions. The species is also expanding its range again and has repopulated , among others, Scotland (from 1954), Central France (from 1985), Thuringia and Rhineland-Palatinate (from 2003) and Lower Saxony (from 2004). In Bavaria , after the last breeding occurrences were extinguished in the 1950s, the first new breeding record was made in 1992 at the Grafenwöhr military training area . In 2005 two breeding pairs brooded here, in 2007 four territorial pairs were identified in the Upper Palatinate .

    The German population increased from around 70 pairs around 1975 to 470 pairs in 2003 and 2004, but is still largely limited to north-east Germany. In the Red List of Germany's breeding birds from 2015, the species is listed in Category 3 as endangered.

    The European population was estimated at 7,800 to 10,300 breeding pairs around the year 2000. The largest European populations at that time had Sweden with 3300–3600 pairs alone, Russia with 2000 to 4000 pairs and Finland with around 1200 pairs. 550 breeding pairs live in Germany, 170 of them in Mecklenburg-Western Pomerania. Today the species is considered harmless worldwide.

    literature

    Web links

    Commons : Osprey  - Album with pictures, videos and audio files

    Individual evidence

    1. ↑ M. Wink, H. Sauer-Gürth, H.-H. Witt: Phylogenetic differentiation of the Osprey (Pandion haliaetus) inferred from nucleotide sequences of the mitochondrial cytochrome b gene. In: RD Chancellor, B.-U. Meyburg (Ed.): Raptors Worldwide. Berlin 2004, ISBN 978-963-86418-1-6 , pp. 511-516.
    2. ↑ T. Mebs, D. Schmidt: The birds of prey in Europe, North Africa and the Middle East. Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-09585-1 , p. 117.
    3. ↑ D. Schmidt and R. Wahl: Horst- and partner loyalty ringed fish eagle Pandion haliaetus in East Germany and Central France. Vogelwelt 122, 2001: pp. 129–140.
    4. ↑ T. Mebs, D. Schmidt: The birds of prey in Europe, North Africa and the Middle East. Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-09585-1 , pp. 112-113.
    5. ↑ Thomas Rödl, Bernd-Ulrich Rudolph, Ingrid Geiersberger, Kilian Weixler, Armin Görgen: Atlas of the breeding birds in Bavaria. Distribution 2005 to 2009 . Verlag Eugen Ulmer, Stuttgart 2012, p. 75
    6. ↑ D. Schmidt: Osprey (Pandion haliaetus). In: K. Gedeon, A. Mitschke and C. Sudfeldt (eds.): Breeding birds in Germany. Hohenstein-Ernstthal 2004, ISBN 3-9806583-5-X , pp. 10-11.
    7. ↑ Christoph Grüneberg, Hans-Günther Bauer, Heiko Haupt, Ommo Hüppop, Torsten Ryslavy, Peter Südbeck: Red List of Germany's Breeding Birds , 5 version . In: German Council for Bird Protection (Hrsg.): Reports on bird protection . tape 52 , November 30, 2015.
    8. ↑ T. Mebs, D. Schmidt: The birds of prey in Europe, North Africa and the Middle East. Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-09585-1 , p. 112.