Small woodpecker

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Small woodpecker
Little Woodpecker ♂ (Dryobates minor)

Little Woodpecker ♂ ( Dryobates minor )

Systematics
Class : Birds (aves)
Order : Woodpecker birds (Piciformes)
Family : Woodpeckers (Picidae)
Subfamily : Real woodpeckers (Picinae)
Genre : Dryobates
Type : Small woodpecker
Scientific name
Dryobates minor
( Linnaeus , 1758)

The small woodpecker ( Dryobates minor , syn .: Dendrocopos minor ) is a species of bird from the genus of the great spotted woodpecker ( Dendrocopos ). These belong to the subfamily of the real woodpeckers in the family of the woodpeckers (Picidae). With a body length of around 15 cm, the species is one of the smallest real woodpeckers. It is distributed in 11 subspecies over the entire western and northern Palearctic to the Asian Pacific coast. In Central Europe, the small woodpecker is a widespread, but not frequent breeding bird. Like many small woodpeckers, the small woodpecker looks for its food mainly in the outer branch area of ​​the tree canopy and is therefore difficult to determine. Some authors assign it to the genus Dryobates together with three small woodpeckers that occur in North America .

Appearance

Adult female

The small woodpecker is a typical representative of the great spotted woodpecker with black and white contrasting plumage, nevertheless it is unmistakable in the western and central Palearctic due to its small size. Although only about the size of a bullfinch , the compact, short-necked and short-tailed, rounded bird looks massive and larger. The small woodpecker is the only European and West Asian great spotted woodpecker that has no red or pink markings in the rump area and on the under tail-coverts. The white-backed woodpecker, which is otherwise noticeable in all great spotted woodpeckers, is missing in the small woodpecker. When viewed from the back, it is reminiscent of the white-backed woodpecker, from which it also differs significantly in its small size.

Males of the subspecies D. m. hortorum wear a brick-red, black-edged cap. The white, at times slightly creamy-yellow face is bordered by a distinct black rein, a beard and a cheek strip; the latter does not connect to the black neck band. The forehead is white, the beak, which is quite long for the woodpecker's body size, up to 18 millimeters, is slate gray. The shoulders are black, the back is white and has a ladder-like, black banding. The distribution of the white and black parts of the back is one of the most important distinguishing features between the subspecies. The upper side of the hand and arm wings is clearly banded in white on a black background. The folded tail is black on top and white on the underside, with black banding. The two outermost control feathers are white and have clear black markings. The underside of this subspecies is very light, almost white; only the breast shows a slightly yellowish hue. The flanks are clearly black with vertical lines.

The sexes do not differ in weight, in the color drawing only in the color of the crown, which is uniformly black in the female. The isabel-colored drawing above the base of the beak extends to the front part of the female, in the nominate form and the breed D. m. hortorum to the middle of the skull. The youth plumage resembles the female plumage, but is paler.

Dimensions and body mass

The length of the small woodpecker varies between the subspecies: The subspecies D. m. Kamchatkensis is the largest with up to 16 centimeters, D. m. quadrifasciatus is the smallest at just under 14 centimeters. The wingspan is between 24 and 28 centimeters. The weight of both sexes varies between 20 and 25 grams.

Age

The oldest ring bird in Central Europe was a female at least 10 years old in Sweden. In addition, a 7 year and 3 month old specimen was found in Switzerland. A bird that was ringed in the year of its birth was found 60 kilometers from the ringing location after about six years.

Possible confusion

There is no possibility of confusion in Europe, West, Southwest or Central Asia. Only in the extreme east of Asia does the distribution area of ​​the small woodpecker overlap with two similarly sized great spotted woodpeckers , the kizuki woodpecker ( Dendrocopos kizuki ) and the gray- headed woodpecker ( Dendrocopos canicapillus ). The former has clearly brown ear-covers and a brown breast with an otherwise similar appearance, the latter differs from the small woodpecker by a clearly gray crown and brown facial markings.

voice

Both sexes of the small woodpecker are very fond of reputation almost throughout the year. The peak of singing activity, however, comes in late winter and early spring. Since the woodpecker is often in the treetops and some of its vocalizations are rather quiet, it can easily be overheard. The main call of both sexes, but especially of the male, is a lined up, light Kikikiki that stays on the same pitch and consists of at least 8, but usually more (up to 20) individual elements. It is vaguely reminiscent of the kestrel's call series , but is a bit quieter, higher and the individual elements follow one another more quickly. A typical Kixen can be heard all year round ; it is brighter and quieter than that of other great spotted woodpeckers . In aggression and other excitement situations , it can be ranked as a scolding . The typical contact call, which can only be heard from close proximity, is a simple, short chack or tjak .

Both sexes of the small woodpecker drum. This instrumental sound is used primarily in late winter and early spring to delimit the territory. Mostly dry branches serve as resonance bodies, but occasionally also metal covers of telegraph poles or television antennas. The quiet, high, very fast and even drum rolls consist of up to 30 beats and last almost 2 seconds. Up to 15 vortices can be made in a minute. The drumming of the females is a little slower and shorter; the distances between the vertebrae are greater.

distribution

green: breeding area of ​​the small woodpecker

The large distribution area of ​​the small woodpecker extends from North Africa, where the species is represented in a small remaining occurrence in Eastern Algeria and Tunisia , through Spain, Portugal and France, all of Central Europe and most of Northern Europe across Russia to Kamchatka , Sakhalin , Hokkaidō and Manchuria and north korea . In the northwest the species reaches England and Wales , but does not breed in Scotland and Ireland . Large parts of Italy, Hungary and the Balkans , the coastal mountains of Turkey, the Caucasus region and Transcaucasia as well as northern Iran and parts of the Zagros Mountains are populated in the south and south-east . Except for a small occurrence in the south of Sardinia , the species is not found on any Mediterranean island. Denmark has only been a breeding area since the early 1960s; it is continuously from the north with birds of the nominate form and from the south with woodpeckers of the subspecies D. m. hortorum settled. In winter Denmark is home to important winter quarters for northern European birds. The northern limit largely follows the tree line and drops steadily from about 70 degrees north in Norway to the east to 60 degrees north. The southern border is formed by the steppes and desert areas of Central and East Asia.

The densest distribution is in the planar and colline stages. Small woodpeckers breed significantly less often in Central Europe in higher areas. The highest nesting site in Central Europe was found in Austria at 1,440 meters in the Dead Mountains in Styria . On Mount Olympus , breeding sites are known from over 1,600 meters above sea level. Small woodpeckers breed regularly up to an altitude of 2,000 meters and above in the Caucasus and Northern Iran.

hikes

The small woodpecker is dependent on its occurrence , resident bird , barnacle or migratory bird . Nordic populations regularly move south; many Swedish and Norwegian small woodpeckers overwinter on Jutland and in northern Germany. Occasionally, mostly parallel to great spotted woodpecker invasions, there are strong incursions of northern small woodpeckers into Central Europe; the last major invasion took place in the winter of 1962/1963, when some small woodpeckers of the nominate form were also found on the Randecker Maar . In Central Europe the birds of the subspecies D. m. hortorum largely resident birds. The Jugenddispersal is little research settlements in distances of more than 20 kilometers from the birthplace seem, however, often occur.

habitat

The small woodpecker makes relatively high demands on its habitat. It prefers forest areas and trees with a good population of old, coarse-barked deciduous trees. Softwood species such as poplar , willow and alder are important, as is a high proportion of standing deadwood and trees in their decay phase. Furthermore, some tall, isolated deciduous trees are important requirements for a good small woodpecker habitat. The species is most likely to find such biotopes in alluvial forest areas, in alder quarries or moist oak - hornbeam forests , in forest areas neglected in terms of forestry or in the colline and montane level on sun-exposed, deciduous slopes with a high proportion of deadwood. In the north and in the eastern boreal zone it inhabits loose birch and alder trees, in the south mainly light oak forests. With a few exceptions, especially in Greece, the species avoids closed, pure coniferous forests, but can stay in coniferous forests with a high proportion of hardwood. Pure beech forests are only occasionally chosen as a breeding habitat. As secondary habitats, the small woodpecker populates parks, orchards, cemeteries, sometimes even larger gardens, if the available food resources are sufficient and there are opportunities to build caves.

The population densities are very different: In optimal habitats of lesser spotted woodpecker population densities as can Buntspecht required, so up to two breeding pairs on 10 hectares, but such values are absolute special cases. In general, the space requirement is significantly larger. The average area size is between 50 and 100 hectares; however, these feeding grounds are restricted to an intensively used core area during the breeding season.

Systematics

The systematic position of the species is currently somewhat confusing. Most authors combine the small woodpecker with other great spotted woodpeckers in the rather extensive genus Dendrocopos , in which small to medium-sized woodpeckers with predominantly black and white plumage are grouped together. The 20 representatives of the genus Dendrocopos occur in Eurasia and North Africa. Until a few years ago Dendrocopos was united with related, especially nearctic species in the genus Picoides . Other authors still summarize all Holarctic great spotted woodpeckers under the generic name Picoides . Recent DNA studies revealed a close relationship with the small woodpecker Dryobates cathpharius and the Downy ( Picoides pubescens ) and two other small nearctic species, P. nuttallii ( Nuttall's Woodpecker ) and P. scalaris ( Texas Specht ). It is considered possible that the ancestors of the small woodpecker from the Nearctic colonized the Palearctic, so the small woodpecker would be one of the few old resettlers among the bird species. These relationships take into account the German scientific naming, which places the small woodpecker in the genus Dryobates , a generic name that was previously used for the small American relatives mentioned above.

Over 20 subspecies have been described, of which eleven are currently recognized. Most of the subspecies mix in the contact zones and produce intermediately colored offspring. There are two groups: the northern group with three subspecies and the southern group with eight subspecies. Overall, the differences are minor and fluid.

  • D. m. minor ( Linnaeus 1758): The nominate form occurs in northern continental Europe up to the Urals . The underside of this large subspecies is very light, almost white; the black markings of the white back are very reduced.
  • D. m. kamtschatkensis ( Malherbe 1861): the northernmost and, following Bergmann's rule, the largest and brightest subspecies. The underside is pure white, the flank lines are almost completely missing. The back is also white, without any black markings. It occurs from the Urals to the southern Anadyr region and on Kamchatka.
  • D. m. amurensis ( Buturlin 1908): This subspecies, which is also large, is gray-white on the underside. Otherwise it is very similar to the nominate form. It occurs in the Amur and Ussuri regions , in northeastern Manchuria , in northeast Korea , on Sakhalin and on Hokkaido.
  • D. m. hortorum ( CL Brehm 1831): This subspecies is distributed from France across Central Europe to Poland, southwards in Switzerland and Hungary. It mediates between the northern and southern subspecies. It is slightly smaller than the nominate form, the back is partially banded in dark gray, the underside is gray, the breast shows a slightly yellowish hue.
  • D. m. buturlini ( Hartert 1912): This subspecies distributed in the Mediterranean, the northernmost occurrence of which is in southern Switzerland , is found sparsely in Spain, as well as in southern France, in the Balkans and in Greece. It differs from D. m. hortorum due to the much darker underside, which is more longitudinally striped on the flanks.
  • D. m. ledouci ( Malherbe 1855): This small subspecies occurs only in a few distribution islands in the Maghreb . It is very controversial because the Spanish buturlini in particular are indistinguishable from it. As a rule, they show a uniformly black beak and a slightly light brown chest.
  • D. m. comminutus ( Hartert 1912): Only occurs in England and Wales. Besides the green woodpecker and the great spotted woodpecker, it is the only species of woodpecker there. This subspecies is also very similar to buturlini , but on average somewhat smaller; the flank stripes are more indistinct than with buturlini .
  • D. m. danfordi ( Hargitt 1883): This small subspecies from eastern Greece and Turkey is also very similar to buturlini . Usually, the drawing on the underside is a little darker, almost light brown. In typical specimens, the cheek stripe extends to the black neck band, so that the cream-colored ear covers are framed almost completely in black.
  • D. m. colchicus ( Buturlin 1908): This subspecies occurring in the Caucasus and Transcaucasus is somewhat larger than the previous one, but otherwise hardly differs from it.
  • D. m. quadrifasciatus ( Radde 1884): This subspecies occurs only in southeastern Azerbaijan on the Caspian Sea . It is the smallest subspecies and has the shortest beak at 12 millimeters. It looks quite dark on the upper side, the underside is also darker than that of buturlini , the flanks are even more clearly striped. The outer control springs are clearly and extensively banded in black.
  • D. m. morgani ( Zarudny & Loudon 1904): This subspecies inhabits north-west Iran and isolates northern parts of the Zāgros Mountains . It differs from all other subspecies by the long, very thin beak and the brown throat with an otherwise white chest and belly side. The black cheek band always touches the neck region. The male's red feathers are limited to the forehead.

food

Aphids are an important food for the small woodpecker

The food of the small woodpecker consists of small tree-dwelling insects almost all year round. In late spring and summer, various types of aphids can become the main food; small caterpillars, beetles and beetle larvae , moths and their larvae and, to a lesser extent, snails , such as bowl snails , are also eaten. Aphids are also the most important prey for rearing young. Tree-dwelling ants, especially the glossy black wood ant or the strange garden ant, play only a minor role in the northern populations, but can form an important part of the diet for some southern subspecies. Large carpenter ants and their stages of development are only eaten if their nests have previously been opened by another species of woodpecker. Occasionally galls, especially those of the common oak gall wasp and the common rose gall wasp , are hacked up and the larvae eaten. In late autumn and winter, the main food consists of beetles, mainly longhorn beetles , weevils and bark beetles , which overwinter under the bark or on leaves. Wood-dwelling larvae are also eaten in winter. The focus is on species that first live under the bark and only penetrate later, such as the blue billy goat .

Vegetable food only plays a subordinate role. In the spring, tree sap that escapes from the ringlets of other woodpeckers or from bark injuries is exploited. Small woodpeckers have occasionally been observed ingesting various berries or pecking ripe fruits. Conifer seeds seem to play some role only in the northern subspecies. In winter, small woodpeckers occasionally appear at bird feeders, where they especially consume the fat from titballs and sunflower seeds .

Food acquisition

The small woodpecker looks for its food mainly in the crown area, very often on thin, outer branches. It is seldom seen on trunk sections and almost never on the ground. The food is mainly obtained by quickly, restlessly looking through branches and leaves, as well as by poking into coarse bark. While poking, the small woodpecker repeatedly chops up small areas, but only gets into the outer areas of the bark. The chopping activities become more intense during the winter months when the small woodpecker food consists mainly of wood-dwelling beetle larvae and beetles that overwinter under the bark. Very often the woodpecker hangs upside down on a thin branch to look for leaves on the underside. His movements are kleiberartig nimble, often it is upside down to see on branches or trunk sections. It captures flying insects quite skillfully through quick arterial flights, occasionally it spends some time just chasing swarming insects from a convenient vantage point. Otherwise, the length of stay in a branch is usually only short: frequent changes of location in the crown area are characteristic of this species.

Vegetable food is taken in directly from the fruit-bearing tree or shrub, for example by picking apples or plums, and occasionally olives, or picking berries from the bush. In winter, reed areas are often visited and reed stalks are hacked up, which various insects use as wintering quarters; The small woodpecker also opens the dry stalks of mugwort or various card species in search of overwintering insects. The little woodpecker does not forge ; Food objects to be processed are clamped into the next best column and chopped up there.

behavior

Like all woodpeckers, the small woodpecker is diurnal; its activity begins just before sunrise and ends just after sunset. The activity peaks are in the early morning and late afternoon. Outside the breeding season, there are extended rest and cleaning phases in between. Bad weather shortens the day's activity, and in heavy rain, small woodpeckers also seek out a sleeping den during the noon rest hour. The nights are always spent in self-made sleeping caves, very rarely does the small woodpecker visit abandoned caves of other woodpeckers or nesting boxes. The morbid condition of the cave trees forces the species to continuously rebuild suitable sleeping caves.
During the rest periods, the small woodpecker carefully cleans and preenes its plumage; Dust bathing was observed several times, caged birds also bathe intensively in the water, the head being completely submerged and then the body being wetted with flapping wings.

Territorial and antagonistic behavior

Male small woodpeckers are territorial all year round, provided they are not forced to pass by weather conditions. Females tend to be more mobile, but if possible also remain in the breeding area, where loose contact with last year's breeding partner can be maintained; Former breeding partners can use sleeping caves in the immediate vicinity. It is not known to what extent females claim territories outside the breeding season. During the breeding season, the area is vigorously defended by both partners against conspecifics. Small woodpeckers even react immediately to incompletely played sound mock-ups, usually with an approach and acoustic presence, sometimes with a direct approach. It is noticeable that females react more aggressively to invading sexual mates and also attack them directly, while males behave more aggressively towards males outside their territory. In addition to the direct approach, which also leads to body contact, ritualized behaviors are often shown , especially the freezing position : the opponents sit almost motionless on a branch opposite each other, bend their head feathers and spread arm and hand wings as well as the control springs . Overall, despite its small size, the small woodpecker is a robust and well-fortified bird, which sometimes knows how to successfully defend its den even against larger woodpeckers - especially against the great spotted woodpecker, which is one of the most important enemies of the species. Smaller cave space competitors such as collar snapper or nuthatch are usually sold successfully. Compared to its main enemy, the sparrowhawk , it usually tries to flee into the dense crown area, where the bird of prey cannot follow it.

Breeding biology

Courtship and pairing

Small woodpeckers become sexually mature at the end of their first year of life. To run a season marriage , Wiederverpaarungen old breeding partners, however, are due to the loyalty to the location of the type often. A loose partner contact often persists even during the winter months. Successive polyandry , in which a female lays her eggs in the burrows of two males, does not seem to be rare; occasionally, however, polygyny may also occur. Also cooperative breeding is likely to occur in rare cases.

As with most woodpeckers, sexually motivated behaviors cannot be clearly separated from territorial and antagonistic ones . In mild winter weather, drumming and long series of calls begin again in December, become more intense as a result and reach their peak in March and April. As early as late winter, females can react to this with approaching and drum responses, whereupon the males show impressive, gliding-hovering sightseeing flights, in which the tail is often stilted during the gliding phase. Often these mating flights lead to a tree with an already existing or started breeding cave. This is indicated by the male with opened wings and demonstrative knocking; the female can follow with drooping, trembling wings, occasionally it also picks symbolically at the brood cavity. The mating is now complete and soon afterwards, at the end of March and in April, copulations near the breeding cave occur.

Nesting site and cave construction

Small woodpecker, adult female at nesting hole

The small woodpecker builds his burrows almost exclusively in trees that are in an advanced phase of decay, very often also in dead, often very thin side branches. In the case of a cave system in largely horizontal branches, the entry hole always points downwards. A number of tree species can be used as nesting trees, almost always trees with soft woods, such as different types of willow , poplar , alder or birch . Often fruit trees, in particular apple trees, are also used, provided that the respective state of decay enables a cave to be built. Nesting holes in conifers were very rarely found.

Due to the frailty of the respective nesting trees, a new nest box is usually created every year. Both partners are working on their completion, the male however more intensely than the female. On average, the duration of the cave construction is two weeks, with a volume of almost a liter being carved out. However, replacement cavities can also be completed in less than a week. Small woodpecker caves can be created in very low-lying trunk sections of one to two meters, but are usually located at a greater height of 5–8, often more than 20 meters. The cave itself is 12-18 centimeters deep with an average width of 10 centimeters; the entrance hole is largely circular with an average diameter of 34 millimeters.

Clutch and brood

Dendrocopos minor

Egg-laying begins in Central Europe in mid-April, fresh full-laid clutches can be found here until the end of May. In Northern Europe and Siberia, the laying period begins at the beginning of May at the earliest and lasts until June; in the southern breeding areas, breeding begins in March. Small woodpeckers only breed once a year, only if there is an early clutch loss will there be a mostly smaller additional clutch. A full clutch consists of 4–6, in exceptional cases up to 9 pure white, short oval eggs with an average size of 19 × 14.5 millimeters, initially with pink air through the translucent yolk. The eggs laid at a daily interval are firmly incubated by both partners from the penultimate one, whereby, as with almost all woodpeckers, the male sits on the clutch during the night. The young hatch after an average of 11 days; they are huddled and fed by both parents. The nestling period is around 20 days, from the 14th to 15th On the 1st day the nestlings appear at the entrance hole to hand over their food. During this time until they fly out, the young birds are acoustically very noticeable. Towards the end of the nestling period, the parents reduce their feedings noticeably, often ending up with food in their beak near the nesting cavity, thus encouraging the nestlings to fly out. After the fledgling, the young birds are looked after by their parents for around two weeks, sometimes divided into two groups. After that the family association disperses; the young birds usually only migrate over short distances.

Existence and endangerment

The population situation of the small woodpecker is very difficult to assess. Due to its small size and its way of life in the treetops, it is not easy to identify, and the drum and call activity can be very different from person to person, so that especially single breeders are not noticeable acoustically. For example, there is a lack of reliable figures that would allow a precise assessment of the population in large areas. This is especially true for the non-European breeding areas. The IUCN sees indications of a slight population decline, but still classifies the species as LC IUCN 3 1st svg(= least concern - not endangered). BirdLife Europe sees no cause for concern and rated the stock in Europe with secured (secure).

The inventory trends are regionally different. Most of the small woodpecker populations appear to be shrinking in south-eastern Europe; The reasons for this are likely to be found in large-scale changes in habitat, in particular in the drainage of wetlands and the clearing of old orchards. In addition, the preference for the spruce in reforestation benefits the great spotted woodpecker, but not the small woodpecker. The stocks are also falling in central Central Europe; here, among other things, the competition with the great spotted woodpecker , which is the most important nest predator of the small woodpecker, is mentioned as the reason . These negative developments are offset by population increases in the Netherlands and Denmark , where the small woodpecker has only been a breeding bird since 1960 and 1964, respectively. The populations are also increasing in Schleswig-Holstein , Mecklenburg-Western Pomerania and Brandenburg . In the short term, the widespread Dutch elm disease increased the population of this woodpecker species.

Worldwide inventory assessments do not exist. In Europe, the breeding population is estimated at around 220,000 pairs. The most important occurrences are in Germany (16,000–32,000 pairs), Poland (20,000–40,000), Belarus (12,000–20,000) and Hungary (20,000–30,000). In Austria and Switzerland the breeding population is around 3,000 pairs each.

literature

Web links

Commons : Little Woodpecker  - Collection of images, videos, and audio files

Individual evidence

  1. ↑ Gorman (2004) p. 144
  2. ↑ HBV (1994) Vol. 9, p. 1103
  3. ↑ Bauer et al .: The Compendium of Birds in Central Europe. 2009, p. 799
  4. ↑ R. Staav: Longevity list of birds ringed in Europe. In: EURING Newsletter 2. 1998, pp. 9–17.
  5. ↑ HBV (1994) Vol. 9, p. 1106
  6. ↑ Winkler (1995) p. 258
  7. ↑ Bergmann (1982) p. 220
  8. ↑ Gorman (2004) p. 146
  9. ↑ Hölzinger (2001) p. 480
  10. ↑ Gorman (2004) p. 153
  11. ↑ HBV (1994) Vol. 9, p. 1098
  12. ↑ Dvorak (1993) p. 267
  13. ↑ Gatter (2000) p. 473
  14. ↑ a b c Hölzinger (2001) p. 484
  15. ↑ HBV (1994) Vol. 9, p. 1106
  16. ↑ Gorman (2004) p. 147
  17. ↑ Dvorak (1993) pp. 266-267
  18. ↑ Index of Scientific Bird Names (2007)
  19. ↑ Weibel & Moore (2001) pp. 70-71
  20. ↑ Archive link ( Memento from May 10, 2008 in the Internet Archive )
  21. ↑ Helbig (2005)
  22. ↑ HBW (2002) Vol. 7, p. 310
  23. ↑ Winkler (1995) pp. 259-260
  24. ↑ Gorman (2004) p. 148
  25. ↑ a b HBV (1994) Vol. 9, p. 1109
  26. ↑ Gorman (2004) p. 149
  27. ↑ Romero & Perez (2008)
  28. ↑ Hölzinger (2001) p. 483
  29. ↑ Factsheet Birdlife international (2006)
  30. ↑ a b Factsheet Birdlife Europe (2005)
  31. ↑ HBV (1994) Vol. 9, p. 1112
  32. ↑ HBW (2002) Vol. 7, p. 477
This article was added to the list of excellent articles on February 26, 2008 in this version .