Helmeted woodpecker
| Helmeted woodpecker | ||||||||||||
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Helmet woodpecker ( Dryocopus pileatus ) |
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| Scientific name | ||||||||||||
| Dryocopus pileatus | ||||||||||||
| ( Linnaeus , 1758) |
The helmeted woodpecker ( Dryocopus pileatus , syn .: Hylatomus pileatus ) is a species of woodpecker from the genus Dryocopus within the subfamily of the real woodpeckers (Picinae). If, as can currently be assumed, the emperor woodpecker and ivory woodpecker are extinct, this species of woodpecker, widespread in North America, will be the largest woodpecker on the continent. It is closely related to the Palearctic black woodpecker . Helmet woodpeckers are woodpeckers that feed on various large species of ants as well as larvae of wood-boring beetle species. Except for mostly small-scale compensatory movements, helmet woodpeckers are very faithful to their location and do not leave the breeding area even in severe winters. Like the native black woodpecker, the helmeted woodpecker is an important supplier of caves: abandoned breeding and sleeping caves are used by a number of bird species, but also by mammals and reptiles. The helmeted woodpecker served Walter Lantz as a template for the cartoon character Woody Woodpecker .
Appearance
The helmeted woodpecker is almost unmistakable due to its size, its black and white zoned face and the noticeably elongated red head. His vocalizations are so characteristic that confusion can be ruled out.
With a maximum body length of 49 centimeters and a weight of up to 350 grams, helmet woodpeckers are only slightly smaller and lighter than black woodpeckers. As with all Dryocopus species, the females are smaller and lighter, with the helmeted woodpecker this size difference is quite noticeable at up to 15 percent. Helmet woodpeckers look extremely long and slender when they sit down, and the neck in particular appears very thin. The body plumage is black with the exception of an individually differently sized white area on the bases of the outer arm wings and the hand wings. Depending on the state of the plumage, this black is dull charcoal or shiny, and with different incidence of light it also has a metallic iridescence. The back looks a bit lighter and sometimes appears slightly gray-black flocked. Adult woodpeckers in both sexes wear a bright red feather bonnet, which is tapered towards the back and tapered to a slightly erect head. A narrow, black eye mask stretches over the eye, which is narrow at the top, but with a wide white border at the bottom; the lower white border runs over the entire lateral neck and lateral front back and is associated with the white drawing of the lower wing in most subspecies. The beak is very long with up to six centimeters, dark slate gray on the upper side and much lighter on the lower side. The tip of the beak is dark gray to black. The iris of both sexes is yellow-orange. The four-toed slate-gray feet and the leg are ringed white. In flight, this woodpecker looks black except for the white facial markings and the wide white markings on the lower wing. The long distance flight of the helmet woodpeckers is largely straight when the wing beats are very deep.
Females are somewhat smaller, forehead and cheeks are striped gray-yellow in them, the red head is not elongated to the same extent as in the males. The red streak of beard, which begins at the lower beak base in the males and continues to the base of the neck, is absent in the females. Young birds are duller in color, the black tones play slightly into the brownish - otherwise the juvenile plumage is similar to the female plumage; at the end of the first year of life, young birds molt into adult plumage.
The helmeted woodpecker could be confused with the ivory woodpecker if visibility is poor; probably the alleged sightings of the ivory woodpecker in Arkansas are also due to such mix-ups. Apart from the size, the ivory woodpecker is well characterized by the wide white markings on the neck and back, the black cap and the long, ivory-colored beak.
Vocalizations
The helmeted woodpecker is an acoustically very noticeable type of woodpecker. He has a large number of different calls and call sequences, which, however, are very different and difficult to transcribe. Most characteristic is the sequence of calls, often circumscribed as Kiieh ... kiii ... kiih . It begins with a few separated, longer drawn individual elements and increases faster and higher to a garish and loud staccato. The stanza consists of up to twenty individual calls and is sexually and territorially motivated. Often Wuuk or Chuuk calls can also be heard. The drum rolls of the helmet woodpecker are relatively slow, so that the individual beats are clearly audible; the eddies carried forward at relatively long intervals can be heard especially in late winter and early spring.
Distribution area
The extremely northeastern breeding areas of this woodpecker species are in Nova Scotia and New Brunswick . To the west they extend over the forest areas of southern Canada and reach the Pacific in British Columbia . To the south, the species breeds in coastal forests and mountainous regions from Washington , Ontario south to central California and in parts of Montana , Nevada , Idaho , Wyoming and Utah . In the east, suitable habitats are populated from southern Canada to Florida ; to the west, the limit of distribution is on the eastern edge of the Great Plains , which the helmeted woodpecker only penetrates along a few wooded river valleys. The main area of distribution is in the humid forest areas of the southeast.
The helmeted woodpecker is not picky about the tree composition of its breeding and feeding biotopes, but it is when it comes to their age structure. It needs old, tall coniferous or deciduous forests that have a certain proportion of trees in their decay phase. Standing or lying dead wood and decaying tree stumps must also be present. High breeding densities near the water indicate a certain affinity for moist biotopes. Helmet woodpeckers breed from sea level to montane regions over 2000 meters.
The settlement density is very different. In optimal habitats, such as the hardwood floodplains in Arkansas , spotted woodpecker areas can be less than 50 hectares, but are usually significantly more extensive. The average size is 500 hectares, suboptimal areas extend over more than 10 square kilometers.
Systematics
The genus Dryocopus includes eight species of large to very large woodpeckers with mostly black or black-and-white plumage. Most of the parietal plumage is elongated and colored red. Four woodpeckers of this genus have their main distribution area in the neotropical , two in the paleotropic and one each in the nearctic or in the palaearctic fauna region. Dryocopus pileatus forms a super species with the line woodpecker ( D. lineatus ) and the black-bellied woodpecker ( D. schulzi ). The breeding areas do not overlap.
New molecular genetic studies suggest a taxonomic revision of the apparently paraphyletic genus Dryocopus . The oldest genus name Hylatomus is available for the five nearctic / neotropical large woodpeckers that were previously included in Dryocopus . It was introduced in 1858 by Spencer Fullerton Baird for the helmeted woodpecker.
Up to four subspecies are described, but only D. p. abieticola ( Bangs 1898) and the nominate form D. p. pileatus ( Linnaeus 1758) The representatives of the subspecies D. p. which breed in the northern and northwestern areas of distribution . abieticola are slightly larger and more often have gray markings on the throat and chest. With them the gray flocculation of the dorsal plumage is clearer than with the slightly smaller birds of the nominate form, which appear uniformly black on the upper side. The breeding areas of D. p. pileatus are east and southeast of Kansas and extend east to the Atlantic coast and south to Florida and the Gulf coast.
Food and subsistence
Helmet woodpeckers feed mainly on forest-dwelling ants, especially representatives of the horse ants ( Camponotus sp.) And wood ants ( Formica sp.) As well as larvae of wood-boring beetles. Other insects such as flies, lice or caterpillars only play a subordinate role. In addition, fruits, nuts, seeds and berries are consumed to a lesser extent.
Helmet woodpeckers systematically search their habitat both on the ground and in the trunk and branch area for suitable food objects. In this process, insects are picked up from the surface, preyed under bark sections by pounding and prying away pieces of bark, and exposed through extensive and far-reaching chopping. The long, pointed tongue, which is kept moist with sticky saliva, plays an essential role in the acquisition of food and can penetrate far into the tunnels of prey. Nothing is known about the use of forges and the construction of food depots.
Breeding biology
Helmet woodpeckers reach sexual maturity at the end of their first year of life, but breeding pairs in which both partners are in their second calendar year are rare, most are in their third calendar year or are older. The helmeted woodpecker is likely to be in a permanent monogamous marriage. In addition to rows of shouts and drum rolls, sightseeing flights, ritualized cave construction and cave displays are the most important elements of courtship and pairing. The nest box is created in late winter and spring in various coniferous and deciduous trees. In the north of the distribution area, conifers such as Douglas fir , hemlock or purple fir predominate , in the south deciduous trees such as oak , elm or sycamores (especially Platanus occidentalis ) are in the foreground. Dead or damaged trees are preferred, but the species is able to cut the nest holes into healthy wood. The caves are created by both sexes in mighty trees, almost exclusively at heights over 15 meters. The entrance hole is oval, the dimensions are 5.5 × 4.5 centimeters. Usually a full clutch consists of four (1–6) pure white eggs with an average size of 33 × 24 millimeters. Laying of the southernmost populations begins at the beginning of March, in northern or higher nesting areas in April and early May. There is little information on the incubation period that suggests a range between 15 and 18 days. During the first 8 days, the nestlings are continually hovered by one parent, usually the female, later the feeding parents only slip in to hand over the food; in the last week of the nestling period, which lasts around 28–32 days, the parents feed at the entrance hole. The tour lasts until early autumn, only then does the family association dissolve. Little is known about the youth dispersal ; Observations in Oregon indicate only small-scale dispersal migrations.
Breeding success and lifespan
As far as is known, the average breeding success of the species appears to be relatively high. In Oregon, young woodpeckers flew out of 83 percent of the 42 nests examined, and the breeding success was 2.26 individuals / breeding pair. In Alberta , a slightly larger sample yielded even more favorable figures: out of 104 nests, 97 youngsters flew out (93.3 percent); 2 cubs from 29 nests and 3 cubs from 68 nests.
Little data is available on the service life. About 60 percent of the young birds survive the first calendar year. Two birds ringed when they were young were found after more than 9 years.
Stock situation and risk
The total population of the species is currently estimated to be around 1 million individuals. Since 1966, there have been significant increases in populations in the western and north-western breeding areas. In particular, forestry measures and the decrease in hunting pressure are held responsible for this. In particular, trees are felled later so that they can achieve larger trunk diameters. In many state forests, living and dead trees with a trunk diameter of over 50 centimeters are no longer removed. On the other hand, there is a decrease in population, especially in the southeast of the distribution area, which can be attributed to a general reduction in forest cover since the 1970s.
The main predators of the helmeted woodpecker are various birds of prey such as the hawk , round-tailed caterpillar or red-shouldered buzzard, as well as large owls such as the great horned owl or the barred owl . Resting and breeding birds as well as nestlings or clutches are preyed on by squirrels, martens and tree-climbing snakes such as the peanut snake .
The direct persecution has decreased significantly over the past few decades, but it still plays a role. However, more important stock-minimizing factors are interventions in the habitat such as deforestation, road construction and mining activities.
swell
Sources cited
- ↑ calling order of the Pileated Woodpecker: Chuk-calls - drums} ( Pileated Woodpecker. In: Birdweb . Seattle Audubon , accessed on April 24, 2019 (English). )
- ^ Evelyn L. Bull, Jerome A. Jackson (2011) Home Range
- ^ TiF - Piciformes Checklist
- ↑ Winkler (1995)
- ↑ Winkler, H. & Christie, DA (2002). Pileated Woodpecker (Hylatomus pileatus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, DA & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/56286 on October 30, 2014)
- ^ TiF - Piciformes Checklist
- ^ University of Wisconsin - Digital Collection
- ↑ Evelyn L. Bull, Jerome A. Jackson (1995) Systematic
- ↑ Evelyn L. Bull, Jerome A. Jackson (2011) Breeding
- ↑ Evelyn L. Bull, Jerome A. Jackson (1995) Breeding
- ↑ Evelyn L. Bull, Jerome A. Jackson (2011) Breeding
- ↑ Evelyn L. Bull, Jerome A. Jackson (1995) Immature Stage
- ^ Evelyn L. Bull, Jerome A. Jackson (2011) Annual And Lifetime Reproductive Success Western US and Canada.
- ^ Evelyn L. Bull, Jerome A. Jackson (2011) Life Span And Survivorship
- ↑ data sheet BirdLife international pdf engl.
- ^ Evelyn L. Bull, Jerome A. Jackson (2011) Trends: Geographic And Temporal
- ^ Evelyn L. Bull, Jerome A. Jackson (2011) Predation
literature
- Evelyn L. Bull, Jerome A. Jackson: Pileated Woodpecker (Dryocopus pileatus). In: The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology 1995 - BNA 148 / (BNA).
- Evelyn L. Bull, Jerome A. Jackson: Pileated Woodpecker (Dryocopus pileatus). In: The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology 2011 - BNA 148 / (BNA).
- Factsheet Birdlife international. (engl.)
- David Sibley: Birds of Eastern North America. Christopher Helm-London, 2003, ISBN 0-7136-6657-9 , p. 253.
- 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
- Videos, photos and sound recordings of Dryocopus pileatus in the Internet Bird Collection
- Hylatomus pileatus inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved February 2, 2014.