Red-headed woodpecker
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Red-headed woodpecker ( Melanerpes erythrocephalus ) |
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| Melanerpes erythrocephalus | ||||||||||||
| ( Linnaeus , 1758) |
The red-headed woodpecker ( Melanerpes erythrocephalus ) is a species of woodpecker from the genus Melanerpes within the subfamily of the real woodpeckers (Picinae). The highly fragmented range of the unmistakable, about the size of a great spotted woodpecker, includes the central and eastern parts of the United States and small areas in southern Canada . The subspecies described on a case-by-case basis are not generally recognized.
Appearance
With an average size of around 22 centimeters, the red-headed woodpecker is just under the length of the native great spotted woodpecker. Characteristic and eponymous is the shiny, uniformly purple head; this color also extends to the neck and throat area. The entire belly, the rump, the underside of the wings up to the hand wings, the rear back and the rump as well as the upper arm wings up to the large coverts are pure white. The upper back, the upper wing cover feathers as well as the upper and lower side of the hand wings are black, the feather edges show a fine light edge there. The tail is black above and below, only the outer flags of the outermost tail feathers are wholly or partially white. The beak is bluish-gray and darker towards the tip, the iris is dark brown. The red-headed woodpecker is one of the few woodpeckers with no visible sexual dimorphism in terms of color, size and weight. In its range it cannot be confused with any other bird species.
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Young birds of both sexes can be clearly distinguished from colored birds: The head and neck area is brown-gray, the throat is brown-gray with clear black longitudinal stripes. The ventral side is flocked whitish, but noticeably brown-gray, the back is flocked brown-black, the arm wings are also banded brown-gray on the top and bottom subterminally. In the late winter of the first year of life, the red-headed woodpeckers change to adult dress.
Vocalizations
Red-headed woodpeckers have an extremely diverse sound repertoire; rough and screeching sequences of sounds, reminiscent of those of jerks or stranglers , predominate. In addition, cackling, sometimes finely chirping sequences of sounds can also be heard. Most sounds are poorly vocalized and therefore difficult to transcribe. In addition to a rather short and not very frequent drumming, there is a hoarse, repeatedly repeated, explosively uttered Quhiiiieh ... the most striking territorially or sexually motivated call.
distribution and habitat
The red-headed woodpecker is mainly found in the east and midwest of the United States. The northeastern breeding areas are in Vermont and New York , although the mountain ranges in these states - such as the Adirondacks - are not populated. The species is very rarely found as a breeding bird in Southeast Canada . To the west, the deposits in Canada reach southern Manitoba and southern Saskatchewan as well as the neighboring states of the USA to the south. In the northwest, the limit of distribution lies in Central Montana and extends southwards along the foothills of the Rocky Mountains via Wyoming , Colorado and New Mexico to central and southern Texas . Starting from this distribution limit in the west, the breeding area of the species extends back to the Atlantic coast , southeast to South Florida . The species is unlikely to occur, or only very rarely, in the Appalachian Mountains and in the adjacent highlands.
The red-headed woodpecker is nowhere common in this wide range. He inhabits largely open landscapes that are only loosely covered with deciduous trees; He avoids closed forest areas, especially coniferous forest areas. Relatively high abundances are found along rivers lined with willow and poplar trees, in human-designed habitats such as orchards, golf courses and occasionally in large parks. Open spaces caused by forest fires or large clearings, but also an increased proportion of dead wood caused by storm events or harmful insects can significantly increase the breeding densities of this species in the short term. In winter it can also appear in high grass steppes far away from trees and, following abundant food sources, invasively in areas in which it otherwise does not or only very rarely occurs.
hikes
The migration behavior largely depends on the food supply, especially that of acorns, maple and pine seeds. In the entire distribution area, no population can be described as obligately local, although red-headed woodpeckers often stay in the breeding area during the winter. Only the northernmost and westernmost breeding areas are regularly cleared in winter. Wandering behavior is more of an undirected roaming than a purposeful move. Red-headed woodpeckers can appear invasive in regions where they have not been seen for decades, or disappear for years in areas where they were common in winter. The autumn migratory movements usually take place during the day, individually or in small groups, often with other birds such as the blue jay . Since there are hardly any observations about the homecoming, it is assumed that the woodpeckers migrate at night.
Food and subsistence
The red-headed woodpecker is largely omnivorous . Its insect diet consists of flies, beetles (more rarely beetle larvae), grasshoppers, dragonflies and other insects. Often eggs from different bird species and occasionally their nestlings are also eaten. Small rodents are also rarely preyed on. In terms of vegetables, the species consumes various nuts, the seeds and fruits of some deciduous tree species, especially those of maple and oak . Cultivated grains are also essential, especially corn, but also fruit and berries. A representative study of over 400 stomach contents, obtained from the entire distribution area throughout the year, showed a quantitative distribution of 33 percent animal and 67 percent vegetable food.
According to its distribution in only loosely tree-covered regions, it has developed some non-woodpecker-typical behavior in acquiring food. Despite its considerable size, the red-headed woodpecker is a skilled hunter of flying insects; Food captured in this way may be seasonal. Otherwise, he preyed on insects by systematically searching trunk or branch sections, by drilling and poking in cracks and crevices, and more rarely by deeper chopping. Foraging takes place in all trunk and branch sections, in the air and on the ground. Hard food objects are processed in forges so that they can be consumed.
Throughout the year, but especially in autumn and winter, red-headed woodpeckers create food depots in various places, especially in cracks in the trunk and in the bark. Such depots were also found under railway sleepers and roof shingles and in other, more unusual places. The food objects are wedged so tightly into the cracks or chopped up crevices found that they can only be removed with difficulty by other animals; Often these depots, in which mainly nuts and, more rarely, insects are kept, are covered by pieces of bark.
Territorial behavior and reproduction
Red-headed woodpeckers occupy territories throughout the year; However, breeding and winter territories are usually not identical. The breeding territories are vigorously defended by both partners, at least in the core areas, and very aggressively against conspecifics; The climax of the intraspecific aggressiveness is in April and June, i.e. in those months in which the first brood and possibly the second brood are brought up. During the post-breeding season, the territories dissolve, but can also disintegrate into partner territories. The size of the territories is very different depending on the food supply; it is astonishingly small for a woodpecker of this size, usually significantly less than 10 hectares. In winter the territories are even smaller, as only the depot places, but not the food sources themselves, are defended.
The red-headed woodpecker is a very aggressive, defensive species that usually has the upper hand in disputes about sleeping and breeding caves. The red-headed woodpecker often remains the winner even against much larger competitors such as the helmeted woodpecker . The introduced and rapidly spreading starling , which has become a problematic cave competitor for many North American cave breeders, is rarely successful against the red-headed woodpecker.
Red-headed woodpeckers become sexually mature in their first year of life; they have a largely monogamous seasonal partnership, but there are indications of polygyny . Reparations of last year's breeding partners are frequent due to the species' great loyalty to the breeding site. The courtship ritual consists, in addition to loud series of calls, above all from reciprocal flight hunts and a game of hide and seek, which is common with many species of woodpecker, in which the partners sit face to face on a trunk at the same height, alternately make eye contact to the right or left and, at times, quickly turning around the trunk, changing positions.
Red-headed woodpeckers seem to create a new nesting hole every year, so in their habitat they are important suppliers of tree holes for many birds and mammals. The type of cave trees varies greatly from region to region, deciduous trees predominate; Telegraph poles in otherwise largely treeless surroundings are also chosen as the cave location. Tree species with soft wood and dead wood are preferred. The nest holes are usually at a height of over 5 meters, very often not in the trunk itself, but on the underside of a strong, almost vertical branch. Barkless or heavily resinified trunk or branch sections are conspicuously preferred, as these are apparently less easy to reach by tree-climbing snakes. Within 2–3 weeks, both partners can create a new breeding cave, the highly oval to round entry hole of which measures a little over 5 centimeters on average. The distance between the nesting holes is different, occasionally two different pairs of nesting holes can be created in a tree or a telegraph pole.
Without the entry of nesting material, 4–7 (3–10) pure white eggs measuring 25 x 19 millimeters are laid on the loose chipboard base. As is common in many bird species, large clutches contain stunted eggs. There are usually two broods a year, one in April and one in June. Both parents brood firmly from the penultimate egg, the male apparently a little more often and always during the night. After about 13 days, the chicks hatch and are fed with food for at least a further three weeks by both parents initially, but most recently by the male. Occasional brood aid seems to occur.
The lead time afterwards is about a month. It is not uncommon for family groups to hike together.
Life expectancy and natural enemies
The one-year survival rate is around 67 percent. A nest ringed bird was found after 9 years and 11 months. Red-headed woodpeckers are an important source of food for some birds of prey such as peregrine falcons and round-tailed corsair. Eggs and nestlings are preyed on by various species of the climbing snake family , but also by mammals such as raccoons .
Systematics
In addition to the nominate form, Avibase also names the subspecies M. e. caurinus from the extreme west and south-west of the distribution area, which often has a slight red color in the lower abdomen, as well as the average smaller and darker breed M. e. brodkorbi from the southeast. However, both subspecies are often not recognized.
Molecular biological investigations established the closest relatives of this woodpecker species to the West Indian Melanerpes species such as the scarlet breast woodpecker ( Melanerpes portoricensis ) and the Guadeloupe woodpecker ( Melanerpes herminieri ); the close relationship with the acorn woodpecker ( Melanerpes formicivorus ) suspected by some researchers was not confirmed in these studies.
Inventory and inventory development
The stocks of the red-headed woodpecker are declining sharply throughout the range. The IUCN therefore puts him on the so-called “warning list” (“NT = near threatened”). Exact analysis of the population showed for the years 1966–1996 a population decline of an average of 2.2 percent annually in the entire distribution area; for the years 1986–1996 this annual decrease was 4.7 percent. Particularly significant, with annual rates of decline of over 5 percent, are the decline in stocks in the Great Lakes region , in Florida and in parts of Ohio .
Until the mid-19th century, the red-headed woodpecker was a very common bird. Because he caused damage in the corn fields and orchards, he was massively persecuted; in some states, shooting bonuses were paid. At the beginning of the 20th century the rock insect , a species of locust found in the prairies and the eastern Rocky Mountains, became extinct. As a result, the western populations of the species almost came to an end. When the American chestnut and American elm disappeared almost everywhere due to introduced diseases and the resulting open landscapes offered new habitats for the red-headed woodpecker, the populations recovered again by the middle of the last century. The current decline in the population is mainly attributed to habitat destruction, the negative impact of car traffic and, despite its robustness and assertiveness, the rapid spread of the naturalized star.
Others
The red-headed woodpecker plays a certain role in North American cultural history. With the Cherokee he was a symbol of war and struggle. In Longfellow's epic The Song of Hiawatha , the species also appears in this martial context. Many different names, such as White-shirt, Half-a-shirt, Jellycoat, Flag Bird, and Flying Checker-Board are evidence of its popularity in North America.
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literature
- David Sibley: Birds of Eastern North America. Christopher Helm, London 2003, ISBN 0-7136-6657-9 .
- Kimberly G. Smith, James H. Withgott, and Paul G. Rodewald: Red-headed Woodpecker (Melanerpes erythrocephalus) In: A. Poole (Eds.): The Birds of North America Online. Ithaca: Cornell Lab of Ornithology, species 518 (BNA)
- Donald and Lilian Stokes: Stokes Field Guide to Birds: Eastern Region . Little, Brown and Company, Boston 1996, ISBN 0-316-81809-7 .
- Hans Winkler , David Christie and David Nurney: Woodpeckers. A Guide to Woodpeckers, Piculets, and Wrynecks of the World. Pica Press, Robertsbridge 1995, ISBN 0-395-72043-5 .
Single receipts
- ↑ a b BNA (2000) Migration
- ↑ BNA (2000) Major Food Items
- ↑ BNA (2000) Food Habits
- ^ BNA (2000) Spacing
- ↑ a b c BNA (2000) Breeding
- ↑ David L. Leonard: Do Abandoned Woodpecker Cavities Provide Secondary Cavity Nesters Protection from Climbing Snakes? In: Southeastern Naturalist March 2009: Vol. 8, Issue 1, pp. 121-128.
- ↑ Megan R. Atterberry-Jones and Brian D. Peer: Cooperative Breeding by Red-Headed Woodpeckers In: The Wilson Journal of Ornithology 122 (1): 160-162. 2010
- ↑ Megan R. Atterberry-Jones and Brian D. Peer: Cooperative Breeding by Red-Headed Woodpeckers In: The Wilson Journal of Ornithology 122 (1): 160-162. 2010
- ↑ a b c BNA (2000) Demography
- ↑ Data sheet Avibase (2003) engl.
- ^ BNA (2000) Systematics
Web links
- Brief profile with a good voice example
- Drums, territorial call, and several birds screeching in between
- Videos, photos and sound recordings on Melanerpes erythrocephalus in the Internet Bird Collection
- Melanerpes erythrocephalus in the endangered Red List species the IUCN 2010. Posted by: BirdLife International, 2008. Accessed August 21 of 2010.
