Little Owl

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Little Owl
Little Owl

Little Owl

Systematics
Class : Birds (aves)
Order : Owls (Strigiformes)
Family : Real owls (Strigidae)
Genre : Aegolius
Type : Little Owl
Scientific name
Aegolius funereus
( Linnaeus , 1758)
The feathered toes are easily recognizable
An owl

The rough owl ( Aegolius funereus ) is a small owl from the species-poor genus Aegolius , which also includes three other species native to North, Central and South America . The strictly nocturnal species inhabits the Holarctic boreal coniferous forest belt as well as low mountain ranges and mountain ranges in Europe, Asia and North America which are split up like islands. Recently, a strong tendency to spread in lowlands has been observed in Central Europe.

The rough owl lives in old coniferous forests or mixed forests dominated by coniferous wood. It is also rarely found in pure deciduous forests. Like most owls, it is cave-breeder and therefore relies on natural tree hollows or caves of larger woodpecker species such as black woodpecker or helmeted woodpecker . Its diet consists mainly of rodents and , to a lesser extent, birds.

Currently five subspecies are usually described, none of which appear in a hazard level of the IUCN .

Appearance

The owl, about the size of a little owl, with a body length of 24 to 26 centimeters, is easy to identify . The span is 53 to 60 centimeters. The sexes differ significantly in weight (♂ around 115 grams, ♀ up to 200 grams), but not in appearance; however, the females are slightly larger.

The large head with the bright field of vision and the black-rimmed face veil is striking. There are no spring ears . The iris of the eyes is bright yellow, under the eyes on both sides of the beak there is a dark, line-like pen drawing. The brown plumage on the upper side is covered with distinct, pearly white dots. The underside is light gray and has gray-brown spots and faded longitudinal stripes. The short feet are feathered white up to the claws, which gives the owl its German name. Young birds are more uniformly colored dark brown, the white spots contrast even less with the dark plumage. The eyebrows and the “beard stripe” are strikingly white.

voice

The singing of the barnacle owl is unmistakable: it consists of four to ten very quickly lined up flute elements on "u (ü)", which rise in height, begin cautiously and become significantly louder and at the end sound pure and resounding "uuü". In good conditions, the singing can be heard up to 2000 meters and its tone is reminiscent of the sound of an ocarina . There are also various other calls, especially a tawny owl-like "kjuwitt". Instrumental sounds such as beak snaps and clapping wings are less common . The singing activity only begins when it is completely dark and can continue until dawn with an interruption in the middle of the night. The first singing peak in Central Europe is in January; during the autumn courtship this species is not very conspicuous. The barn owl can be heard most frequently during the main breeding season in April and May. The vocal activity of the species is not very high overall and can be almost completely stopped in the presence of predators, especially the tawny owl ( Strix aluco ). Call of a male barnacle owl:

distribution

Distribution of the rough owl:
  • Year-round occurrence
  • Wintering areas

    • The species is distributed in large parts of the Holarctic , with the distribution area extending through the Holarctic belt of coniferous forests in Europe, Asia and North America. Some populations south of it are considered to be relics from the last Ice Age . A total of seven subspecies are described, six of which live in Eurasia, one in northern North America. The subspecies are not very differentiated in appearance; to the east the white markings of the individuals become clearer and their plumage is therefore lighter; the size of the subspecies also increases somewhat to the northeast. The American subspecies Ae. f. richardsoni , on the other hand, is darker again and more closely resembles the nominate form.

    Six of these subspecies breed in a wide belt from Scandinavia , the Baltic States , large parts of Russia , Siberia , Mongolia and northeast China to the Pacific ( Kamchatka and Sakhalin ). The nominate form Ae lives here . f. funereus in Europe eastwards to the Urals , followed by the distribution areas of Ae in North Asia . f. pallens and Ae. f. magnus . In Central Asia there is mainly Ae. f. sibiricus represented. Geographically isolated there are some mountain populations in the Caucasus ( Ae. F. Caucasicus ) and in Tianshan ( Ae. F. Beikianus ). The breeding area of ​​the North American subspecies Ae. f. richardsoni stretches from the Atlantic to the Pacific and essentially includes central and southern Canada in a belt of different widths. In some places the distribution extends deep into the United States, in the northwest the subspecies reaches Alaska.

    The breeding area of Ae. f. funereus is divided into islands in Central Europe and is essentially limited to low mountain ranges and alpine locations up to the tree line . The species has also been found in the Carpathian Mountains and in some forest islands of the Dinaric Mountains , in northern Greece and as the westernmost occurrence in the Pyrenees . In north-eastern France, eastern Belgium, the Netherlands and some parts of northern Germany and Poland, lowland areas are increasingly being populated. The closed breeding area begins in southern Sweden and extends in a wide belt to the Urals. In Finland the distribution reaches 70 ° N and subsequently stretches in a wide strip between ~ 50 ° N and the Arctic Circle to the east, south of it there are still some islands of distribution in the Central Russian ridges , the Crimean Mountains and on the Black Sea coast of Turkey ( Pontisches Mountains ).

    habitat

    Large, old and contiguous forests, especially with firs , spruces and beeches , and sometimes pines, are preferred as habitats . The species breeds more rarely in pure beech forests ; but it also occurs in sparse larch forests and loosened birch trees. In North America, the species prefers stands of black spruce and white spruce , interspersed with poplar , birch and balsamic fir . At higher altitudes, it is preferably found in forests with rocky mountain firs and Engelmann spruces . The often claimed exclusive link between the species and the spruce does not exist. In addition to sufficient food, the breeding ground must also have enough breeding caves, especially black woodpecker caves, in North America caves of the golden woodpecker and the helmeted woodpecker . Daytime shelters with plenty of cover must be easily accessible and free hunting areas, such as clearings or afforestation, must be available.

    A strong presence of predators ( pine marten , tawny owl , eagle owl , in North America, especially Barred and spotted owl and various Mustelidae , especially the American marten ) prevents new companies and can lead to the abandonment of breeding grounds.

    As a boreal species, the main vertical distribution in Central Europe is between 800 and 2000 meters, but deep-lying broods are also more common in Central Europe, for example in the Lüneburg Heath, in southern Brandenburg, in the Vienna Woods (330 m), or near Munich (520 m) m). The settlement of lowland areas in eastern Germany is particularly clear, where 15% of the entire breeding population of the species is made up of populations that live in habitats below 250  m above sea level. NN brood. In the Rocky Mountains the barn owl can be found up to heights of 3000 meters.

    behavior

    Food and subsistence

    Little Owl with a captured yellow-necked mouse

    The rough owl feeds exclusively on animals. Its prey consists of small mammals, mainly rodents and, to a lesser extent, birds up to about the size of thrushes .

    Voles ( earth vole and bank vole ) and real mice ( wood vole and yellow-necked mouse ) make up the main part of the diet in Central Europe. Shrew species and dormice are also preyed on . In the mammalian proportion, voles predominate with over 50% of the total. Bird bones are always found in the ridges , but their proportion is usually less than 9%.

    The species hunts mainly during the night; daytime hunts have only been found in the northernmost distribution areas (especially on very cloudy days and during the rearing of young). The rough owl is a waiting hunter; Search or chase were rarely observed. The rough-owl apparently locates its prey almost exclusively acoustically and hits it on the ground after a shock flight. This extremely nocturnal way of hunting is mainly made possible by the strongly asymmetrical arrangement of the external auditory canals, which can be seen in many species of owls, but is particularly impressive in this species. The prey animals are mostly divided, only rarely swallowed whole, birds are at least partially plucked. During the breeding season, barnacles create food depots, especially in black woodpecker caves, which can contain considerable amounts of prey.

    Rest and comfort behavior

    The activity phase begins at dusk and ends before dusk. In Central Europe, a midnight break interrupts this activity, but this break is absent on the short northern European summer nights. In contrast to the pygmy owl or little owl, the almost silent flight is straight. Even during the breeding season, the owl usually spends the day in a shelter, especially in dense conifers, in physical contact with the tree trunk. Niches or tree hollows are rarely used. The barn owl rests while standing by slightly fluffing its plumage and pulling its head towards its body; in this position it can sometimes be completely snowed in in winter.

    Occasionally, however, the resting place is left to care for plumage and to sunbathe ( comfort behavior ). Bathing in water or snow is very common, and rain showers are also common. To sunbathe, the animal sits on exposed branches and ruffles its plumage, sometimes spreading its wings downwards.

    Social and enemy behavior

    The males in Central Europe and especially when there is good food availability are often territorial beyond the breeding season, otherwise they are wandering solitary animals, the females tend to wander more strongly. Even during the breeding season, the animals are in different places without maintaining contact with the partner. The territories are marked by chant, the defense is carried out by alarm calls and mock attacks. However, the boundaries are relatively loosely defined and the aggressiveness towards conspecifics is rather low. Social interactions such as mutual nibbling or mutual feathers care have not yet been observed.

    The behavior of the rough owl consists primarily of a pronounced avoidance of enemies. The owls are usually well hidden in their sitting area and camouflaged by their coloration, reinforced by their upright position of rest. Areas with high enemy pressure , e.g. from tawny owls, are generally avoided. When an enemy approaches, the owl first adopts a camouflaging position in which it presses its plumage tightly against the erect body and raises the head veil to two ears. If the threat persists, this posture can change into a threatening position, in which the animal ruffles its plumage and opens its eyes wide. Then the tail fan and, in extreme cases, the wings are fanned out wide.

    Reproduction

    Clutch and food depot in the nest box
    Egg,     Museum Wiesbaden collection
    Fledgling young bird

    Like the owl, the nest box is neither cleaned for the brood, nor is nesting material entered. Black woodpecker caves are mostly used, but the barn owl also accepts suitable nesting boxes. In Central Europe, breeding begins mostly in mid-March. The clutch size is highly dependent on the availability of food and is between two and seven eggs. However, clutches with 9 or more eggs were also observed. After about 33 days, the young leave the brood cavity and are kept as branchlings for at least three weeks, but usually significantly longer. With the autumn courtship at the latest, the family association dissolves and the young birds migrate .

    Most of the barn owls only breed once a year, but if there is a loss of clutch or if there is a very cheap food supply, there are second broods that can also be nested . It is not uncommon for the female to leave the young when they no longer need to be rowed and breed with another partner a second time, sometimes quite far from the first breeding site. In such a case the male takes on the further rearing and management of the young. ( Polyandry ). But polygyny was also found. The pair bonding of the barnacles does not go beyond the breeding season, often even for parts of the breeding period. Occasionally, however, the mating of two breeding partners was also observed over a period of years.

    Migratory behavior

    The Central European birds are predominantly resident birds , whereby the breeding site fidelity of the males is much greater than that of the females. Females also pass considerable distances during the breeding season. Young birds migrate into the surrounding area. Northern European populations show a much more pronounced willingness to migrate, which, following gradations , can also assume the character of an invasion . In particularly snowy winters, breeding birds at higher altitudes seek lower-lying areas.

    Inventory and inventory trends

    The worldwide population of the species is estimated at 1.7 million individuals. Despite local fluctuations, the portfolio development is largely stable. The IUCN assesses the population of the barnacle owl as LC (= least concern). The species has been able to significantly expand its breeding area in Central Europe in the last few decades. This applies to Belgium, the Netherlands and Schleswig-Holstein, Lower Saxony and Brandenburg, for example. In particular, it has benefited from extensive protective measures, above all from the installation of nesting aids and the expansion of coniferous wood plantings. The milder winters could also have contributed to an increase in the population. Today, the Central European population is estimated to be around 7,000 breeding pairs. In Poland and the Czech Republic the barn owl is on the red lists , but throughout Europe the stocks are classified as "S" ( secure ). Due to the sometimes quite low singing activity and the often very inaccessible breeding grounds, the rough-owl is more likely to be counted among the under-recorded species, that is, the actual population numbers could be above the numbers given by Birdlife.

    Name derivation

    The word part “rough” in the species name has become somewhat incomprehensible, it no longer has anything to do with the current meaning of the adjective “rough”, which originally meant “hairy”, “feathered”, furry. In the fairy tale Allerleirauh , the girl wears a robe made of various types of fur.

    Only in the expression “Rauchwerk” for fur goods and in the hunting phrase “rough” for “moult” are leftovers. In ornithology, this term is still used for species whose legs are feathered up to the toes: grouse , buzzard .

    Some names of owls have come down to us from ancient Greece. However, it is now very difficult and often speculative to assign them to a species; aigōliós is one of these names. As a Greek foreign word in the Latinized form aegolius , the name is already used in the Naturalis Historia of Pliny (10, 165). The scientific species name funereus can be translated as belonging to burial , in a broader sense also ominous , and reflects the popular superstition that owls are heralds of an imminent death.

    literature

    Individual evidence

    1. ↑ W. Holt, R. Berkley, C. Deppe, P. Enríquez Rocha, JL Petersen, JL Rangel Salazar, KP Segars, KL Wood: Boreal Owl (Aegolius funereus). (1999). In: J. del Hoyo, A. Elliott, J. Sargatal, DA Christie, E. de Juana (Eds.): Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona 2013. (Retrieved from http://www.hbw.com/node/55095 on July 31, 2014).
    2. ↑ Claus König, Friedhelm Weick: Owls of the World. Christopher Helm, London 2008, ISBN 978-0-7136-6548-2 , p. 442.
    3. ↑ IUCN data sheet
    4. ↑ Birdlife data sheet

    Web links

    Commons : Raufußkauz  - Album with pictures, videos and audio files
    Wiktionary: Raufußkauz  - explanations of meanings, word origins, synonyms, translations
    This article was added to the list of excellent articles on February 13, 2005 in this version .