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Sunday 16 July 2023

Northern goshawk, Goshawk - Accipiter gentilis (Linnaeus, 1758) Διπλoσάϊvo, Διπλοσιάχινο - Cyprus

See also

List of Cyprus birds of prey on this blog - Λίστα Αρπαχτικών πουλιών της Κύπρου σε αυτό το ιστολόγιο

 - Αρπαχτικά πουλιά της Κύπρου

The northern goshawk (/ˈɡɒsˌhɔːk/; Accipiter gentilis) is a species of medium-large bird of prey in the family Accipitridae, a family which also includes other extant diurnal raptors, such as eagles, buzzards and harriers. As a species in the genus Accipiter, the goshawk is often considered a "true hawk". The scientific name is Latin; Accipiter is "hawk", from accipere, "to grasp", and gentilis is "noble" or "gentle" because in the Middle Ages only the nobility were permitted to fly goshawks for falconry.

This species was first described by Linnaeus in the 10th edition of his Systema naturae (1758) as Falco gentilis.

It is a widespread species that inhabits many of the temperate parts of the Northern Hemisphere. The northern goshawk is the only species in the genus Accipiter found in both Eurasia and North America. It may have the second widest distribution of any true member of the family Accipitridae, behind arguably only the golden eagle (Aquila chrysaetos), which has a broader range to the south of Asia than the goshawk. The only other acciptrid species to also range in both North America and Eurasia, according to current opinion, is the more Arctic-restricted rough-legged buzzard (Buteo lagopus) Except in a small portion of southern Asia, it is the only species of "goshawk" in its range and it is thus often referred to, both officially and unofficially, as simply the "goshawk". It is mainly resident, but birds from colder regions migrate south for the winter. In North America, migratory goshawks are often seen migrating south along mountain ridge tops at nearly any time of the fall depending on latitude

Distribution
The northern goshawk has a large circumpolar distribution. In Eurasia, it is found in most areas of Europe excluding Ireland and Iceland. It has a fairly spotty distribution in western Europe (e.g. Great Britain, Spain, France) but is more or less found continuously through the rest of the continent. Their Eurasian distribution sweeps continuously across most of Russia, excluding the fully treeless tundra in the northern stretches, to the western limits of Siberia as far as Anadyr and Kamchatka. In the Eastern Hemisphere, they are found in their southern limits in extreme northwestern Morocco, Corsica and Sardinia, the "toe" of Italy, southern Greece, Turkey, the Caucasus, Sinkiang's Tien Shan, in some parts of Tibet and the Himalayas (India and Nepal), western China and Japan. In winter, northern goshawks may be found rarely as far south as Taif in Saudi Arabia and perhaps Tonkin, Vietnam.

In North America, they are most broadly found in the western United States, including Alaska, and western Canada. Their breeding range in the western contiguous United States largely consists of the wooded foothills of the Rocky Mountains and many other large mountain ranges from Washington to southern California extending east to central Colorado and westernmost Texas. Somewhat discontinuous breeding populations are found in southeastern Arizona and southwestern New Mexico, thence also somewhat spottily into western Mexico down through Sonora and Chihuahua along the Sierra Madre Occidental as far as Jalisco and Guerrero, their worldwide southern limit as a breeding species.
The goshawk continues east through much of Canada as a native species, but is rarer in most of the eastern United States, especially the Midwest where they are not typically found outside the Great Lakes region, where a good-sized breeding population occurs in the northern parts of Minnesota, Illinois, Michigan and somewhat into Ohio; a very small population persists in the extreme northeast corner of North Dakota. They breed also in mountainous areas of New England, New York, central Pennsylvania and northwestern New Jersey, sporadically down to extreme northwestern Maryland and northeastern West Virginia. Vagrants have been reported in Ireland, North Africa (central Morocco, northern Algeria, Tunisia, Libya, Egypt); the Arabian Peninsula (Israel, Jordan, Saudi Arabia), southwest Asia (southern Iran, Pakistan), western India (Gujarat) and on Izu-shoto (south of Japan) and the Commander Islands, and in most of the parts of the United States where they do not breed.

Northern goshawks can be found in both deciduous and coniferous forests. While the species might show strong regional preferences for certain trees, they seem to have no strong overall preferences nor even a preference between deciduous or coniferous trees despite claims to the contrary. More important than the type of trees are the composition of a given tree stand, which should be tall, old-growth with intermediate to heavy canopy coverage (often more than 40%) and minimal density undergrowth, both of which are favorable for hunting conditions. Also, goshawks typically require proximity to openings in which to execute additional hunting. More so than in North America, the goshawks of Eurasia, especially central Europe, may live in fairly urbanized patchworks of small woods, shelter-belts and copses and even use largely isolated trees in central parts of Eurasian cities. Even if they are far more wary of human presence than the Eurasian sparrowhawk, northern goshhawks are known to live in some relatively densely wooded areas of large cities of Central Europe, such as Berlin and Hamburg; it is a relatively new phenomenon that started in the 20th century. Access to waterways and riparian zones of any kind is not uncommon in goshawk home ranges but seems to not be a requirement. Narrow tree-lined riparian zones in otherwise relatively open habitats can provide suitable wintering habitat in the absence of more extensive woodlands. The northern goshawk can be found at almost any altitude, but recently is typically found at high elevations due to a paucity of extensive forests remaining in lowlands across much of its range. Altitudinally, goshawks may live anywhere up to a given mountain range's tree line, which is usually 3,000 m (9,800 ft) in elevation or less. The northern limit of their distribution also coincides with the tree line and here may adapt to dwarf tree communities, often along drainages of the lower tundra. In winter months, the northernmost or high mountain populations move down to warmer forests with lower elevations, often continuing to avoid detection except while migrating. A majority of goshawks around the world remain sedentary throughout the year

Νεαρό έξω από την φωλιά του. Φωτογραφίες στον ποταμό Διάριζο  στον εκδρομικό χώρο Κομιτιτζή κοντά στο χωριό Μυλικούρι στις 18/6/2021

Photos Milikouri 18/6/2021 by George Konstantinou






Breeding
The northern goshawk is one of the most extensively studied raptors in terms of its breeding habits. Adult goshawks return to their breeding grounds usually between March and April, but locally as early as February. If prey levels remain high, adults may remain on their breeding ground all year. Courtship flights, calls and even nest building has been recorded in Finland exceptionally in September and October right after young dispersed, whereas in most of Fennoscandia, breeding does not commence any earlier than March and even then only when it is a warm spring. Most breeding activity occurs between April and July, exceptionally a month earlier or later. Even in most areas of Alaska, most pairs have produced young by May. Courtship flights typical are above the canopy on sunny, relatively windless days in early spring with the goshawks’ long main tail feathers held together and the undertail coverts spread so wide to give them an appearance of having a short, broad-tail with a long dark strip extending from the center. Display flights not infrequently escalate into an undulating flight, similar to a wood pigeon but with sharper turns and descents, and are sometimes embellished with sky-dives that can cover over 200 m (660 ft). One study found undulating display flights more than three times more often done by males than females. After display flights have concluded, the male typically brings a prepared fresh prey item to the female as part of the courtship. In general, these displays are presumably to show (or reinforce) to the potential mate their health and prowess as breeding partner. Copulation is brief and frequent, ranging up to nearly 520 times per clutch (on average about 10 times a day or 100-300 throughout the season), and may be the male's way of ensuring paternity since he is frequently away gathering food by the time of egg-laying, although extra-pair copulation is extremely rare. Female solicits copulations by facing away from male with drooped wings and flared tail-coverts. The male, wings drooped and tail-coverts flared, drops from a branch to gain momentum, then swoops upward and mounts her back. Both birds usually call while mating Fidelity studies from Europe show that about 80–90% of adult females breed with the same male in consecutive years, whereas up to 96% of males mate with the same female in consecutive years. In California, 72% of males retained relationship with the same mates in consecutive years while 70% of females did the same. Males intruding in Hamburg, Germany territories were in some cases not evicted and ended up mating with the female, with the male of the pair not stopping it. In migratory, northernmost populations, mate retention in consecutive years is low. Males are sometimes killed by females during courtship and encounters can be dangerous especially if he does not bring food to courtship and he often seems nervous withdrawing with a trill at a given chance

Nest characteristics
Nesting areas are indefinite, a nest may be used for several years, also a nest built years prior may be used or an entirely new nest may be constructed. When nest constructing, the pair will often roost together. Males construct most new nests but females may assist somewhat if reinforcing old nests. While the male is building, the female perches in the vicinity, occasionally screaming, sometimes flying to inspect the nest. At other times, the female may take a more active role, or even the primary one, in new nest construction and this is subject to considerable individual variation. For the nesting tree, more than 20 species of conifer have been used including spruce, fir, larch, pine and hemlock. Broadleaf trees used including ash, alder, aspen, beech, birch, elm, hickory, hornbeam, lime, maple (including sycamore), oak, poplar, tamarack, wild cherry and willow. In some areas, the nests may be lined with hard pieces of bark and also with green sprigs of conifers. Often the tallest tree in a given stand is selected as the nest tree and this is often the dominant tree species within the given region and forest. Therefore, hardwood trees are usually used as the nesting tree in the eastern United States while conifers are usually used in the western United States. Most nests are constructed under the canopy or near the main fork of a tree and in North America, averaging nest height ranged from 5.8 m (19 ft) (in the Yukon) to 16.9 m (55 ft) (in New Mexico), elsewhere as in Europe average height is between 9 and 25 m (30 and 82 ft In the dwarf trees of the tundra, nests have been found at only 1 to 2 m (3.3 to 6.6 ft) off the ground, and, in the tundra and elsewhere, very rarely on felled trees, stumps or on the ground. In some studies from North America up to 15% of nests are in dead trees but this is far rarer in Eurasia. More significant than species is the maturity and height of the nesting tree, its structure (which should have ample surface around the main fork) and, perhaps most significantly, little to no understory below it. Multiple studies note the habit of nests being built in forests close to clear-fellings, swamps and heaths, lakes and meadows, roads (especially light-use logging dirt roads), railways and swathes cut along power cables, usually near such openings there'd be prominent boulders, stones or roots of fallen trees or low branches to use as plucking points. Canopy cover averaged between 60 and 96% in Europe. As is typical in widely distributed raptors from temperate-zones, those from cold regions faced south, 65% in Alaska, 54% in Norway and also in high latitudes such as sky-forests of the Arizona Rockies, otherwise usually nests face north and east.

Nests, especially after initial construction, may average between 80 and 120 cm (31 and 47 in) in length and 50 to 70 cm (20 to 28 in) in width, and are around 20 to 25 cm (7.9 to 9.8 in) deep. After many uses, a nest can range up to 160 cm (63 in) across and 120 cm (47 in) in depth and can weigh up to a ton when wet. Northern goshawks may adopt nests of other species, common buzzards contributed 5% of nests used in Schleswig-Holstein, including unusually exposed ones on edges of woods and another 2% were built by common ravens or carrion crows, but 93% were built by the goshawks themselves. While colonizing peri-urban areas in Europe, they may displace Eurasian sparrowhawks not only from their territories but may actually try to use overly small sparrowhawk nests, usually resulting in nest collapse.[9] One nest was used continuously by different pairs for a period of 17 years. A single pair may maintain up to several nests, usually up to two will occur in an area of no more than a few hundred meters. One nest may be used in sequential years, but often an alternate is selected. During an 18-year-study from Germany, many alternate nests were used, 27 pairs had two, 10 had 3, 5 had 4, one had five and one pair had as many as 11. Other regions where pairs had on average two nests were Poland, California and Arizona’s Kaibab Plateau. The extent of use of alternate nests is unknown as well as their benefit, but they may reduce significant levels of parasites and diseases within the nest. In central Europe, the goshawk's nest area can be as small 1 to 2 ha (2.5 to 4.9 acres) of woods and less than 10 hectares are commonplace. Usually only one active nest occurs per 100 ha (250 acres), are they avoid edges as nest sites and occupied nests are seldom less than 600 m (2,000 ft) apart.[clarification needed]  The most closely spaced active nests by a separate pair on record was 400 m (1,300 ft) in central Europe, another case of two active nests 200 m (660 ft) apart in Germany was a possible case of polygamy. From Wikipedia, the free encyclopedia

                                                      Eggs



Subspecies
Accipiter gentilis albidus
Accipiter gentilis apache
Accipiter gentilis arrigonii
Accipiter gentilis atricapillus
Accipiter gentilis buteoides
Accipiter gentilis fujiyamae
Accipiter gentilis gentilis
Accipiter gentilis laingi
Accipiter gentilis marginatus
Accipiter gentilis schvedowi (eastern goshawk)

Photos Armirolivado 2022 and  Marathasa valley 2023 by Constantinos Antoniou





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