Blood-faced woodpecker
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Blood-faced woodpecker ( Melanerpes lewis ) |
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| Melanerpes lewis | ||||||||||||
| ( GR Gray , 1849) |
The blood face Specht ( Melanerpes lewis ) is a relatively large species of the genus Melanerpes within the subfamily of the Real woodpecker (Picinae). The dark-looking, medium-sized woodpecker is sparsely distributed from southwest Canada to the southwest USA. In summer it is primarily a flying insect hunter, a prey acquisition behavior that occurs frequently in the genus Melanerpes , but is particularly pronounced in this species. Blood-faced woodpeckers are not very true to their location and roam far outside of the breeding season. They are among the first species to repopulate forest areas after a fire disaster. The individuals living in northern latitudes usually leave their breeding area in winter. The species, of which no subspecies are described, is not endangered according to the IUCN .
features
With a body length of up to 28 centimeters, the blood-faced woodpecker is slightly larger than a gray woodpecker . The wingspan is up to 53 centimeters, the weight is 100 grams. From a distance, this woodpecker looks largely dark and gloomy. The top is greenish-gray, with the color nuances differing depending on the incidence of light. The neck, throat and chest are silver gray. The clearly black edged field of vision is matt blackish red. The crown and back of the head are black. The iris is also black . There are many tactile bristles at the base of the black, slender, slightly curved beak. The abdomen and rump are reddish in color to varying degrees. The rump and all control feathers are black without drawing, but can have a green sheen.
The sexes do not differ in color from one another; Males are on average slightly larger and heavier; however, these differences are not sufficient for a reliable field ornithological gender assignment.
Young birds are easy to distinguish from colored individuals. The upper side resembles the adult plumage to a large extent, but is less dull and thus appears even darker; The head, neck, cheeks, neck and chest are dirty brown-gray, the flanks are darkly striped on a brownish or brown-silvery background. The abdomen and rump are pale reddish.
The silvery-gray neck area and the long, wide, conspicuously fingered wings are characteristic in flight . In the view from below, the color contrast between the almost black under wing coverts and the much lighter wing feathers is also noticeable.
The flight style of the blood-faced woodpecker differs from all other North American woodpeckers, so that the species was also mistaken for a crow or a jay by the first white observers . Blood-faced woodpeckers fly almost in a straight line, with deep, slow flaps of their wings, which can be followed by longer gliding phases on occasion. The typical woodpecker-like arching flight with wings laid out in the downward movement was not observed in this species of woodpecker.
Vocalizations
Blood-faced woodpeckers are not noticeable acoustically. They also behave rather calmly in the pre-breeding season. Most calls are rather quiet, with high pitched chirping sound sequences. Occasionally, however, a rather far-reaching, multiple-ranked, rough Phrieerr can be heard. Alarm sounds are screeching sequences of calls reminiscent of jays .
The drumming of the blood-faced woodpecker is inconspicuous. The drum sequences are short and sound weak and bright.
distribution and habitat
Currently, the north-westerly breeding occurrences are in southern British Columbia and the southernmost in central New Mexico ; the species breeds southwest to the San Bernardino Mountains and east to the border area of Colorado and Kansas . Outside the breeding season, the main areas of distribution are in the central and southern part of the breeding area. In the south the species occasionally appears on northern Baja California , in northern Mexico and southern New Mexico, as well as in the west on the California Pacific coast and eastward to central Texas .
Within these ranges, the blood-faced woodpecker is generally a rare breeding bird and winter visitor. Regionally, however, it can become common over the years and then disappear again for a long time. It shares this irregular distribution and frequency with the red-headed woodpecker .
The most important props of a cheap blood-faced woodpecker habitat are loose trees with an open crown, a large proportion of standing and lying dead wood, open tree-free sections with bush or grass vegetation, and a sufficient supply of larger insects. He finds these prerequisites above all in open stands of yellow pines , in light, river-accompanying trees , especially poplar trees, and in felling areas or areas affected by forest fires. It is one of those species that were the first to repopulate forest fire areas. In forest fire-damaged stands of the yellow pine, high breeding concentrations of the species are often found a few years after the fire. In addition, the blood-faced woodpecker also breeds in open oak trees, juniper stands as well as in fruit and nut plantations, as long as they find caves there or deadwood is available for cave construction.
The vertical distribution ranges from lowland areas along the rivers to high-altitude areas over 2500 meters in Arizona and Colorado.
Little is known about the size of the territories and the type of territoriality. The blood-faced woodpecker probably only claims the immediate nesting area during the breeding season and the depot places in autumn and winter.
hikes
Blood-faced woodpeckers are resident birds in the central and southern part of their distribution area, but outside of breeding season they roam in small groups in an opportunistic foraging for food. After the breeding season, they often move to higher areas in order to return to lower areas, often also cultivated land, in the middle of autumn. The birds that breed in the northern areas of the distribution area are obligatory migratory birds with a maximum migration distance of more than 1000 kilometers. They leave their breeding grounds at the end of August and overwinter in the more southern areas. Only at the beginning of May do these birds reoccupy their traditional breeding regions. Blood-faced woodpeckers usually migrate during the day and in small groups. At some bottlenecks in their migration routes, such as a longitudinal valley of the Siskiyou Mountains , high migration concentrations of up to 5000 individuals were found in just a few days in autumn.
Food and subsistence
The food spectrum of the blood-faced woodpecker is diverse. In late spring, summer and early autumn, various insect species form the main component of the diet, while the rest of the time the species feeds primarily on seeds, nuts and fruits. Overall, vegetable food predominates.
The insect food consists mainly of sex animals, larvae only play a subordinate role. Ground beetles , ladybirds and scarab beetles make up the largest proportion of the insectivorous food segment , alongside ants , crickets and grasshoppers . Bird eggs and snails are regularly eaten, as well as lizards and small mammals occasionally .
The vegetable diet consists primarily of pine nuts, maple seeds and acorns . In addition, however, a number of other vegetables, such as ripe fruit, cultivated nuts, in particular almonds , the berries of various wild bushes such as those of the dogwood , the rock pear or the elder, and cultivated corn are included. Blood-faced woodpeckers swallow relatively large amounts of gastroliths, particularly in autumn and winter .
Most of the insect prey is caught on the fly. Usually the flying insects are spotted from a hide and are captured in a short hunting flight, but occasionally blood-faced woodpeckers also hunt in a long flight hunt, especially when the insect population is very rich. The beak opening, which is very wide for woodpeckers, should be an adaptation to this hunting method. During the air hunts they are often socialized with other flying insect hunters such as swallows or sailors . Insects are preyed on trunks and branches mainly through intensive searching and poking; Chopping activities to expose wood-boring larvae were not found in this species of woodpecker. Even on the ground, the prey animals are only picked up from the surface; even in rich places, insect passages are apparently not widened by hoeing.
Pine cones, almonds and other hard-shell food objects are carried to a suitable smithy and processed there, or stored in a depot. Fruits and berries are consumed on the spot. The woodpecker usually sits above the fruit cluster, less often it hangs under the food source.
Food depots
In autumn and winter, the blood-faced woodpecker creates food depots in trees, in telegraph poles, and occasionally on log houses or in the wooden cladding of houses. The woodpecker tries to take advantage of cracks and crevices, but also hacks precisely fitting openings in order to pinch the food object. Above all, this is how vegetables, especially pine nuts, acorns and corn kernels are stored, but occasionally also beetles and snails. The time required for this storage is great and far outweighs the time that has to be spent looking for food itself. The quantities in stock can be correspondingly large: a single woodpecker deposited over 10,000 kernels of corn in four standing, largely rotten telephone poles.
Breeding biology
Courtship and cave construction
The breeding biology of this woodpecker species has not yet been adequately researched. Blood-faced woodpeckers are likely to reach sexual maturity at the end of their first year of life. They lead a largely monogamous seasonal marriage; however, there are also indications of long-term couple bonds. In the southern breeding regions, courtship activities begin as early as the end of March and early April, and accordingly later in the north and in higher-lying breeding areas. The courtship rituals consist of typical woodpecker chase flights, calls for this type of woodpecker that are relatively frequent and the selection of a nesting tree with the subsequent cave construction. The nesting holes are created in the trunk area or on a side branch that is as vertical as possible. The nesting trees are always in an advanced state of decay or have already died; trees damaged by fire are also selected as cave trees. The species also uses natural caves or semi-caves as well as caves of other woodpecker species. A clear preference for a tree species was not established. Nesting holes can be found in pine species, especially the yellow pine, in spruce, as well as often in poplars, willows and occasionally in telegraph poles. The nesting height fluctuates considerably: nesting holes can be in an area under two meters, but also at very great heights. The so far highest measured brood cavity of a blood-faced woodpecker was at a height of over 50 meters. The nest boxes are created by both sexes. The inlet opening measures about 6 centimeters in diameter, the size of the cavity varies widely and depends on the decay stage of the nest tree. The chipboard is usually relatively large at a few centimeters.
Clutch and brood
The laying period begins in the low-lying southern breeding areas at the end of April in higher regions and in the north only a month later. Blood-faced woodpeckers only breed once a year, nothing is known about clutches. The last fresh clutches are found in July. Overall, the start of laying is very variable and strongly adapted to climatic conditions. The clutches are large; they contain up to 11 (usually 5 to 7) pure white eggs with an average size of 26 x 20 millimeters. They are incubated by both parents for about 12 to 14 days. As with almost all woodpeckers, only the male incubates at night, which in this species also sits longer on the eggs during the day than the female. The nestling period is 28 to 34 days; During this time the boys are provided with food by both parents. The strongest cubs fly out first and stay in the immediate vicinity of the nesting tree until all cubs have left the nesting cavity. During this time the young birds are particularly exposed to predation by various birds of prey such as kestrels exposed. This flight period can last a few days. When all the young birds have flown out, the family association moves away from the vicinity of the nesting hole. However, the young birds are still fed by their parents for a long time and remain in the parents' association even after this lead time until autumn. Only when the parents start bringing in the winter supplies do the families break up. There are no data available on the youth disposition .
Inventory and inventory development
The status of this species, which tends to be inconsistent, is very difficult to assess; In addition, detailed data is lacking over large parts of the distribution area. Birdlife international assesses the population as largely stable and does not assign the species to any hazard category. This source assumes a total population of around 130,000 individuals. Regional studies, which, however, have to be interpreted carefully due to the generally changing population density, show considerable population declines. Especially in the northernmost, in some cases very well investigated, distribution areas in British Columbia, stocks seem to have declined sharply in the last two decades. There the blood-faced woodpecker is listed as very rare and critically endangered . The blood-faced woodpecker is considered a pointer species, especially in the area of loose, high-montane coniferous forests .
Natural enemies are mainly birds of prey and tree-climbing snakes, among the latter especially the gopher snake ( Pituophis catenifer ). Because of the relatively late start of breeding, the loss of caves to other cave breeders plays only a subordinate role; the blood- faced woodpecker usually has the upper hand compared to the introduced European star , which is rapidly increasing in its population .
Single receipts
- ^ BNA (1997) Introduction
- ↑ BNA (1997) Habitat
- ↑ Abele et al. (2004) p. 15
- ^ BNA (1997) Migration
- ↑ Abele et al. (2004) p. 10
- ^ BNA (1997) Food Capture And Consumption
- ^ BNA (1997) Food Selection And Storage
- ↑ BNA (1997) Breeding
- ↑ BNA (1997) Breeding / Microhabitat
- ↑ Factsheet (2006)
- ↑ Abele et al. (2004) p. 19
- ^ Cooper & Beauchesne (2000) p. 9
- ↑ Abele et al. (2004) p. 8
- ↑ Abele et al. (2004) p. 8
- ↑ Vierling (1998) p. 376
literature
- Stephen C. Abele, Victoria A. Saab and Edward O. Garton: Lewis's Woodpecker (Melanerpes lewis): A Technical Conservation Assessment. USDA Forest Service, Rocky Mountain Region 2004. Full text engl. (PDF; 1.0 MB)
- John M. Cooper & Suzanne Beauchesne: Inventory of Lewis Woodpecker Breeding Population and Habitat in the East Kootenay . Wildlife Working Report; British Columbia 2000; Full text engl.
- Factsheet Birdlife international (engl.)
- David Sibley: Birds of Eastern North America. Christopher Helm, London 2003, ISBN 0-7136-6657-9
- Donald and Lilian Stokes: Stokes Field Guide to Birds: Western Region . Little, Brown and Company, Boston 1996, ISBN 0-316-81810-0 .
- Bret W. Tobalske: Lewi's Woodpecker (Melanerpes lewis) . In: The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online. (= BNA)
- Kerry T. Vierling: Interactions between European Starlings and Lewis Woodpecker at Nest Cavities In: Journal Field Ornithologie 69: 3 (1998) pp. 376–379 full text engl. (PDF; 285 kB)
- 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 .
Web links
- Melanerpes lewis in the endangered Red List species the IUCN 2010. Posted by: BirdLife International, 2009. Accessed August 21 of 2010.