Common buzzard ( Buteo buteo )
|( Linnaeus , 1758)|
The common buzzard ( Buteo buteo ) is a bird of prey from the hawk family and the most common representative of this family in Central Europe . It is medium-sized and compact, the plumage varies from dark brown to almost white. It can often be seen in its circling soaring flights or while hunting from its hide. Small mammals make up the main part of their diet . Habitat are open landscapes such as meadows , fields and heath with adjacent forest areas in which the nest is built.
The common buzzard's distribution area includes all of Europe with the exception of Iceland and the north of Scandinavia . To the east, the area extends to Central Asia . Common buzzards are predominantly part migrants . The wintering areas are in Central Europe, North Africa , the Middle East and India . The subspecies B. b. vulpinus ( Hawk Buzzard ), which breeds mainly in Asia , also winters in Sub-Saharan Africa . The stock is currently not considered endangered.
The common buzzard is a medium-sized, compact bird of prey. It is 51 to 57 centimeters long and has a wingspan of 113 to 128 centimeters . The wings are relatively wide, the relatively short tail is rounded at the end. During the circling glider flight, the wings are set up flat in a V-shape. The tips of the hand wings are always dark, and the tail is usually tightly banded throughout. The goiter area (breast flap) is usually striped lengthways, more rarely monochrome white to black-brown and usually dark even if the underside is otherwise light. The often lighter chest band is dark, longitudinally striped in young birds and transversely banded in adult birds. The under tail coverts are monochrome, spotted or banded. The feathers on the lower legs, the so-called trousers, are monochrome, banded or striped lengthways. The last two plumage parts mentioned can be lighter on dark and darker on light undersides. The tail is the surest feature to distinguish the nominate form of the common buzzard from its subspecies and from the buzzard . In the nominate form of the common buzzard, the tail feathers are gray, brown or rust-red with eight to twelve dark transverse bands. The further coloring and drawing is very variable.
The nominate form of the common buzzard occurs in very different colors from almost completely white to almost completely black-brown in numerous transitions, which is unique in the bird world of Central Europe, apart from the even more variable ruff . A distinction can be made between light, intermediate and dark morphs . The darkest morphs are almost completely clay-colored to black-brown, young birds (from flying out to the first moult) with longitudinal stripes on the underside, some of which also extend over the goiter . The adult birds can have horizontal stripes on the underside up to the darker crop area. The fully banded tail is brown or gray. Intermediate morphs have a less clear markings on the whitish to pale yellowish underside, sometimes without the typical bib on the lower part of the goiter. The tail is sometimes incompletely banded. The lightest morphs with a whitish-pale yellow base color on the underside and back have significantly fewer or almost missing wing and tail bands. Light yellow individuals often have ocher brown and gray spots on their backs, which is why they look "colorful".
This variability is not only reflected in the French name buse variable . For them, attempts have often been made to explain the geographic distribution. However, this connection was questioned early on and later intensively investigated. The distributions of the color variants over larger areas were examined. A connection to reproductive success was also established. To research this connection in detail, buzzards in Germany are equipped with wing tags. As part of a citizen science project, sightings by the population can be reported to the researchers. A molecular genetic study led to the finding of a low enzyme - heterozygosity , from which a hypothesis on the role of a possible genetic bottleneck was erected, dedicated to the high-grade polymorphism could arrange the buzzards.
The horn-colored claws are lighter or darker in all morphs according to the color of the plumage. The beak is black and lighter towards the head. The feathered body parts (feet and wax skins ) are light pink in newly hatched young birds and yellow in adult birds. The iris varies in color from gray, gray-brown to gray, rarely lighter or yellowish and is related to the general color of plumage.
The color of the iris is lighter in young birds than in adult birds.
A reliable distinction between youth and age is possible externally by the design and shape of the tail feathers. In young birds the dark subterminal band is insignificantly wider than the remaining dark band. In adults, the subterminal bandage is significantly wider. The young birds have more pointed tail feathers, the adults more straight ending.
The change from youth to old age takes place in the first moult , i.e. around the age of one year. In doing so, not the entire large plumage is renewed, usually the outermost hand wings remain. This gives the possibility of differentiating birds in the third calendar year (up to two years of age) and older specimens. The first and second downy clothes of the nestlings can be mouse gray or pure white. Nestlings with a mouse-gray downy dress have a white patch on the neck and horn-black claws throughout. This patch on the neck is missing in the white downy dress, and the claws are up to a third white from the tip.
Adult males from Germany weigh an average of 790 g (622 to 1183 g range of variation ), females 990 g (782 to 1364 g). These are normal weights (without starving individuals) on an annual average. The nutritional status was taken into account and the goiter and stomach contents (see below) subtracted. The weight fluctuates considerably over the course of the year, since between the breeding season and winter, on average, up to 130 g (12 to 290 g) in males and up to 180 g (47 to 370 g) in females reserve fat, which is then (mostly by January to April) is almost completely consumed. This corresponds to 14.2 percent of normal weight in males and 15.6 percent in females. Accordingly, the annual maximum weight is reached in November / December. In exceptional cases, the reserve fat can make up around a quarter of the total weight. Most of the food ingested can be found in the goiter. For males, their mass is on average 82 g (max. 156 g), which is 10.4 percent (max. 19.7 percent) of their normal weight, for females 134 g (max. 209 g) of their normal weight 13.5 percent (max . 21.1 percent).
During daily nest checks by climbing the nesting trees between 1988 and 1996 of a total of 15 nests in Drente (northeastern Netherlands ), the average weight of the young birds on the day of hatching was 44.5 g. It was measured in the evening on ten young birds, seven of them males and three females.
The common buzzard is a bird of prey that calls a lot. The loud call, which can often be heard in flight, sounds sloping meowing and is often imitated by the jay . It is the well-known buzzard call "hiääh", which can be heard throughout the year, but mostly during the breeding season. The very similar alarm call begins with a bursting "pi", followed by a less glaring "-jää". It can also be heard from young birds from around 20 days of age. There are no gender specific call characteristics. The alarm call usually has a "more annoying" effect than the more often heard, more "meowing" call.
The young birds beg with "piij piij" from the first day of life, which sounds deeper and stronger from around twelve days. The single sounds then consist of a stressed prefix and a deeper second syllable: "biijüüi biijüüi ...". When the nest is left, i.e. from around the 40th day of life, this sound often only consists of the second half. Depending on how hungry the young birds are, they can then be called in series at intervals of a few seconds up to long pauses. From July these particularly conspicuous begging calls can be heard mainly as location calls away from the nest.
The common buzzard mainly lives in small forest areas with adjacent, open landscapes , where it almost exclusively looks for its food. In the forest environment, he prefers pastures , meadows , heather and wetlands or vegetation that has been kept short by humans . Breeds at altitudes over 1000 meters above sea level are rare. Common buzzards can often be seen sitting on posts along highways as they search these and other routes while hunting. When choosing a nesting site, forest edges of smaller old wood stands are preferred, the interior of closed forests or narrow border strips between fields or individual trees are less common. Increasing colonization of landscapes with few trees was observed on control areas near Potsdam and in the west of Schleswig-Holstein. A high proportion of broods were found in rows of poplars , but also on individual trees and in small trees at a distance of less than a hundred meters from individual farmsteads. These new settlements were already described as not rare before that. There are successful broods in close proximity to houses in the settlement area.
The choice of the type of nest tree, which is usually at least 20 centimeters in diameter at the base, depends on the local offer. In Brandenburg the pine dominates , followed by oak , beech , alder , birch or willow , in the Swabian Alb the beech, far ahead of oak, spruce , fir and the like. a., whereby the nest is built there on average at a height of about 18 meters. The nest is created at the end of the trunk in branches or near the trunk on side branches. So far, two broods in the ground in Schleswig-Holstein and one brood on a high-voltage grid mast have been detected. In recent times, rock broods have also been observed in Germany.
As a cultural successor , the common buzzard has also conquered the city centers as a territory. Here he prefers cemeteries or parks as eyrie locations, sometimes in the immediate vicinity of residential developments.
The nominate form of the common buzzard is common in all parts of Central Europe and is the most common bird of prey. However, the common buzzard is absent in Iceland , in Norway (except for its southernmost part), further in northwestern Sweden and in Finland . The distribution area of the nominate form is limited to the east by the Baltic states, western Belarus , the northwest of Ukraine and the east by Bulgaria and Greece . The further distribution of the species is listed in the section on internal systematics . There are no breeding occurrences in most of Turkey , the entire Middle East, and North Africa . Likewise, most of Ireland and the east of England and Scotland have not been populated since the extinction at the end of the 19th century.
The common buzzard belongs to the buzzard genus , from the hawk family , along with 27 other species worldwide, of which it and another 9 occur in Eurasia and Africa .
The closest relatives of the buzzards are the buzzard , the Upland Buzzard and the Mountain Buzzard , with whom he a super species forms.
There are eleven subspecies:
- Buteo b. buteo ; the nominate form is common in most of Europe, in southern Finland and Sweden and in the northern regions of Turkey.
- B. b. vulpinus ; Also known as the Hawk Buzzard , breeds in northern Sweden, Finland, the European part of Russia and south to the Caucasus and Central Asia. Thus it connects to the spread of the common buzzard in the north and east, overlaps are known. It is less variable in color and on average slightly smaller than B. b. buteo . The underside and tail are often cinnamon, reddish, and have less banding. In Central Europe it occurs as migrant and overwintering, some individuals stay in Poland during the summer . In addition, B. b. vulpinus in sub-Saharan Africa .
- B. b. menetresi ; is together with B. b. vulpinus also known as the steppe buzzard and lives in the Crimea , the Caucasus and northern Iran ; is a rare guest in Southeast Central Europe.
- B. b. arrigonii ; lives in Corsica and Sardinia , is a bit lighter and smaller than B. b. buteo .
- B. b. insularum ; lives in the Canary Islands and is B. b. arrigonii similar.
- B. b. rothschildi ; lives in the Azores , is slightly smaller and darker than B. b. buteo .
- B. b. bannermani ; Also known as Cape Verde buzzard, lives on the Cape Verde Islands , recognized as Buteo bannermani by the IOC as an independent species since 2011 .
- B. b. hispaniae ; lives on the Iberian and Italian Peninsula.
- B. b. harteri ; lives on Madeira Island .
- B. b. trizonatus ; lives in South Africa .
- B. b. socotrae ; also known as Socotra buzzard, lives on Socotra , recognized as Buteo socotraensis by the IOC since 2010 as an independent species.
During the breeding season, buzzards - a territorial behavior - defend their breeding ground around the eyrie tree. During the courtship from mid-February the breeding pairs perform courtship flights over the breeding area. They consist of common, sailing circles in which there is a lot of shouting. This is followed by a sinus-like falling and rising, which is usually ended with a dive to the nest.
Foreign buzzards are driven out of the air space above the breeding area by a quick approach with powerful wing flaps. During the breeding and rearing of young, these border disputes between neighboring pairs become less frequent. Occasionally there can still be arguments with individual foreign buzzards.
Common buzzards tend to be found in loose, widely distributed groups outside the breeding season. This applies above all to areas with a correspondingly high food supply, i.e. meadows, fields and humid lowlands. They are increasingly used by buzzards (including winter guests) in winter. They usually stay there all day, trees are only sought out to sleep. Especially with fallen game and if there is a lack of food in severe winters, groups with appropriate rankings can be formed, i. In other words, there are individual individuals who have priority over their conspecifics, which is also fought for and defended.
"Swarms" of up to eight or more buzzards that can be observed during migration and that gain altitude together in circling soaring only indicate the shared use of updrafts and thermals . Usually these individuals move on individually.
The main food of the common buzzard is small mammals, in Central Europe mainly field mice . He also takes birds, mostly young birds, reptiles , e.g. B. lizards , blindworms and grass snakes , as well as amphibians , mostly frogs and toads . Just like earthworms, insects and their larvae can sometimes make up a small proportion of the prey. In some cases, fish have also been identified as food. These are collected dead or dying. The same applies to larger birds, such as B. Pigeons that are injured, have already died or are parasitized by other birds of prey to feed the common buzzard. He often picks up animals that have been run over on traffic routes and is often run over himself. So far, reliable data on the food spectrum could only be obtained in individual studies from the collected prey remains on the nest or from the analysis of stomach contents. Bulges (spits that contain almost exclusively hair) provide insufficient information about the composition of the food.
The composition of the food can vary greatly depending on regional availability and the varied habitat: In an investigation of remains on the nest in the period 1945–1960 in the area around Castell in Lower Franconia, 70% mammals, 15% reptiles, 12% Birds and 3% amphibians detected. In an investigation between 1981 and 1984 in Berlin and the surrounding area, 59% were birds, 37% mammals, 2% fish and 1% each reptiles and amphibians.
Common buzzards are sexually mature from the age of two to three years, which was determined by observing winged individuals in Wales.
Because of their relatively high territorial loyalty, breeding pairs can stay together for a lifetime. Common buzzards can live up to 26 years.
In Central Europe, egg-laying begins in mid-March, on average it takes place in mid-April. The eggs are on average 56 × 45 mm in size and weigh 50–60 g. They are more or less red-brown and gray-brown spotted on a white background. The clutch usually consists of two to three eggs, clutch with one or four eggs also occur. The eggs are laid two to three days apart. The incubation period is 33 to 35 days and depends on the size of the clutch, since breeding starts later with three and four-nails than with single and two-nails. After hatching, the young buzzards stay in the nest for 42 to 49 days and are then fledged, but still stay on the branches and neighboring trees around the nest. This begging flight phase following the nestling period can last six to ten weeks. Here the boys are increasingly chasing their parents and are cared for by them until they are independent. Then the young buzzards wipe out of the breeding area. In doing so, they are usually only a few kilometers away from their place of birth. In exceptional cases, however, distances of 200 km occurred. The sending of telemetry transmitters to nestling buzzards in southern England also showed that they settled near their place of birth.
The reproductive number, i.e. H. The number of young birds successfully flown out per brood started can vary, depending on the food supply, from 0.73 (in North Wales from 1979 to 1982) and 2.56 (in Scotland from 1969 to 1972). In Berlin and Brandenburg the reproductive rate between 1973 and 1998 was between 1.28 and 2.16, with an average of 1.56.
Of the young birds that are flown out, about 49 percent survive the first year, 68 percent of them the second year and 71 percent the third year. In later years, 81 percent of them are still alive, which was determined on the basis of re-discoveries of young ringed buzzards.
Central European buzzards are resident birds or partial migrants, depending on their distribution area . Most of the population in Western Europe, particularly the British Isles, consists of resident birds. They stay in or near the breeding area all year round. A large part of the Central European buzzards moves less than 50 km away from the breeding area. Such partial drawers are 30 to 40 percent of one-year-old and 50 percent of perennial individuals from Germany. Scandinavian buzzards, on the other hand, are mostly migratory birds whose wintering area extends from southern Sweden, via Denmark, Germany, the Netherlands and Belgium to France.
The furthest migration of a buzzard could be demonstrated on the basis of an individual ringed in northern Sweden, which was found 6335 km from its place of birth in Togo, West Africa. In Falsterbo in southern Sweden, the "eye of the needle" of the Scandinavian bird migration, at the narrowest point of the Baltic Sea between Sweden and Denmark, 10,000 (1987) to 13,000 (1990) buzzards were counted annually during the autumn migration from 1987 to 1990.
The train starts in August, peaks in mid-October and ends in November. The return can begin as early as February, depending on the harshness of winter, but mostly takes place in March and ends in the second half of April. Sudden onset of winter with a surprising amount of snowfall can also lead to buzzards (also resident birds) fleeing from northern regions or high altitudes directly to more southerly or lower-lying areas.
The total population of the common buzzard in the Western Palearctic is estimated at an average of 1,028,000 breeding pairs (at least 783,000 to a maximum of 1,273,000). Estimates from all countries of the Western Palearctic, mostly from the beginning of this millennium, were evaluated. For Germany, the breeding population of the nominate form from data for the individual federal states in the period 2001 to 2005 is given as 96,000 pairs (85,160 to 107,060).
Overall, the population development of the common buzzard since the 19th century is rated as positive due to decreasing persecution, large-scale afforestation and increasing colonization of open land. Since the introduction of all-year-round closed seasons, some Central European stocks have almost reached their carrying capacity again, i.e. the possible number of breeding pairs per area. The common buzzard continues to benefit from the EU set-aside of arable land, which improves the living conditions of field mice. Severe human persecution has resulted in significant population decline and proliferation in some areas. However, since then some areas have not been fully repopulated. This applies particularly to Ireland (one to ten couples in the 1950s) and England, and until at least the 1980s it was indebted by so-called “game rangers”, ie through stalking. For the same decline as well which is rabbit - myxomatosis blamed, with rabbits as main prey, if any, have only regional importance. In the eastern regions of England and Scotland, buzzards have been absent as breeding birds for the past 100 years. Recently, however, these regions have been repopulated.
In the Netherlands , the common buzzard was an extremely rare breeding bird at the beginning of the 20th century, rarer than the goshawk . Due to the heavy use of pesticides in agriculture , the subsequent population increase was severely slowed. In 1960 about 100 dead buzzards were found, which was about half of the population at that time. As early as the mid-1970s, the population had grown to around 1,500 breeding pairs and in the early 1980s to around 3,500 to 4,500 breeding pairs. At the beginning of the nineties, as a result of good mouse years, a particularly large number of settlements were found.
In northern Schleswig-Holstein a population increase of 100 to 200 percent was found on a test area of 1000 km² (102 to 206 breeding pairs in the years 1967 to 1976 and 300 breeding pairs in 1998). 37 percent of the pairs brooded outside of forests in 1998, compared to only 5 percent earlier.
Strong annual stock fluctuations are mostly due to the availability of food. This applies above all to the field mouse, whose populations are subject to cyclical fluctuations (so-called "gradations"), which means that the buzzard populations that rely on them can also fluctuate strongly. If food availability is poor, the proportion of non-breeding animals increases to 40 to 75 percent, as was found in Schleswig-Holstein.
The common buzzard is currently not considered endangered. Kills and reenactments still occur today, especially in the areas of transit and wintering. Common buzzards are subject to hunting law in Germany, but have a year-round closed season in accordance with the EU bird protection directive. Most of the individuals who die in accidents die in collisions on roads and railways or on overhead lines.
Among the birds, buzzards are particularly killed by the rotor blades of wind turbines. In northern Germany, with its already high density of wind turbines, almost 8% of the population per year die in this way. In the study areas in Schleswig-Holstein, a population decline of 76% was found within a decade and a half. In anticipation of the further expansion of wind energy throughout Germany and in combination with other factors such as the increased cultivation of maize fields, which are not usable for the buzzard as hunting areas, experts speak of "extremely worrying" developments and "potential threat to the population".
Germany is home to over 50 percent of the Central European buzzard population and thus bears a certain international responsibility.
The breeding success can fail in many places due to human influence, if z. B. felling or other forestry measures take place during the breeding season in the breeding area. Unawareness can also cause disturbances in the forest that damage breeding or young birds.
Outdated names of the common buzzard are cat eagle and catfish . In Brehms Tierleben it is said: “His voice resembles the meowing of a cat, and it owes its name to it, since the word 'Buse' means cat, so the buzzard was called Katzenaar.” “Buse” is an old New High German Word for cat that is different from the call “bus! bus! ”. The New High German term Aar means eagle and is still partly used in falconry.
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- ↑ Robert Dietrich, Winfried Otto: Population and reproduction of the buzzard Buteo buteo in the east of Berlin 2000–2011. In: Berlin ornithological report , 21st year (2011), pp. 1–15.
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- ^ Forsman 1999.
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- ↑ a b Mebs & Schmidt 2006, p. 365.
- ^ N. Kjellén: Differences in age and sex ratio among migration and wintering raptors in southern Sweden. In: The Auk. 111 (2), 1994, pp. 274-284.
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- ↑ Mebs & Schmidt 2006, p. 360.
- ^ RF Ruttledge: Ireland's Birds . London 1966.
- ↑ Cramp & Simmons 1980, p. 178.
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- ↑ U. Hohmann: Studies on the use of space and breeding biology of the buzzard ( Buteo buteo ) in the west of Schleswig-Holstein. In: Corax. 16, 1995, pp. 94-104.
- ↑ Buteo buteo in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2004. Retrieved on October 22 of 2008.
- ↑ a b Mebs & Schmidt 2006, p. 366.
- ↑ https://www.geo.de/natur/nachhaltigkeit/21698-rtkl-artenschutz-windenergie-und-voegel-die-opferzahlen-sind-viel-hoeher
- ↑ https://schleswig-holstein.nabu.de/politik-und-umwelt/energie/windenergie/22684.html
- ↑ https://www.dda-web.de/downloads/texts/publications/falke/63/falke_63_3_windenergie.pdf
- ↑ K. Richarz, E. Bezzel, M. Hormann (Ed.): Pocket book for bird protection. AULA-Verlag, Wiebelsheim 2001, p. 40 u. 224-225
- ↑ Mebs & Schmidt 2006, p. 359.
- ^ Alfred Edmund Brehm: Brehms animal life. Birds; third volume; Search birds, fin divers, petrels , thrusting birds 3., gänzl. rework. Aufl., Leipzig 1892, p. 340, partial excerpt from a digitized version on Google Books
- ↑ Buse in the German dictionary by Jacob Grimm and Wilhelm Grimm at woerterbuchnetz.de
- Call and photo
- Buteo buteo onthe IUCN Red List of Threatened Species .
- Videos, photos and sound recordings for Buteo buteo in the Internet Bird Collection
- Age and gender characteristics (PDF; 4.2 MB) by J. Blasco-Zumeta and G.-M. Heinze (eng.)
- Common buzzard feathers