Pine jay
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Pine jay ( Nucifraga columbiana ) in Banff National Park |
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| Nucifraga columbiana | ||||||||||||
| ( Wilson , 1811) |
The Clark's Nutcracker ( Nucifraga columbiana ) is a bird art from the family of corvids (Corvidae). The gray-black representative of the nutcracker ( Nucifraga ) reaches a size of 27-30 cm and lives in the Rocky Mountains and their side chains and foothills. It is a characteristic species of the local pine forests specialized and different to the seeds pine species, which he hides throughout the year to feed in the winter of them. The pine jay builds its nest in the crowns of conifers, the clutch is incubated by both sexes in late winter and spring.
The English name "Clark's Nutcracker" was named after the discoverer William Clark , who saw the bird on the Lewis and Clark expedition on August 22, 1805 for the first time and sketched it. After his sketches, the pine jay was described by Alexander Wilson . The pine jay is probably basal in the genus of the nutcracker and forms the sister clade to the pine jay ( Nucifraga caryocatactes ) and Himalayan jay ( N. multipunctata ). The species population is considered safe, but it is heavily dependent on certain pine species and regionally affected by their decline.
features
Build and color
The pine jay is a rather small raven bird with a body length of 27–31 cm. It has a long, thin and slightly curved beak and a slim appearance due to its close-fitting plumage. The sexes are colored the same, but there is a sexual dimorphism in relation to body size. Males are on average larger and heavier than females, but the dimensions overlap. Males reach a wing length of 181–202 mm and a tail length of 104–124 mm. Their beak is 34.8–47.8 mm long and weighs an average of 137 g. Females have a wing length of 180-199 mm. Its tail is 103–117 mm long, while its beak is 34.3–42.8 mm long. The mean weight of the females is 123 g. Like all nutcrackers , the pine jay has a skin pocket behind its tongue in which it can store collected seeds. Both males and females have a fully developed brood spot , which enables the clutch to be incubated alternately.
The nasal feathers , the front forehead, the cheeks and the chin of the jay as well as a thin ring around the eyes are white in adults . The rest of the head, the back and the shoulder covers are mouse gray, the body plumage can be a little darker and browner than the head. On the rump, the gray becomes darker and changes to dark gray to black on the upper tail covers. The belly side of the body is the same color as the back but is slightly lighter. The under tail-coverts are white. The pine jay's feathers are almost completely black and have a metallic-green sheen. Only the lower third of the arm swing is white. The middle pair of control springs is black and has a light green metallic sheen. In the second innermost pair of springs, the inner flags and the base of the outer flags are black, the rest of the control springs are uniformly white. The beak is as black inside and out as the legs. The iris of adult pine jays is brown.
Juvenile pine jays differ from adult birds only in details. The feathers of the body plumage have ocher-sand-colored tips. The young birds also lack the white markings on their faces, instead it is a uniform mouse gray. Overall, the plumage is looser and the inside of the beak only changes from salmon-colored to black over time.
Flight image and locomotion
Pine jays usually stride on the ground, changing to a hopping gait to increase speed. They typically turn their heads left and right to keep an eye on their surroundings. The birds move very agile in the branches. The long-distance flight of the pine jay is reminiscent of ravens and crows ( Corvus spp.): It flies quickly at around 45 km / h and with powerful, even flaps of its wings. He also makes targeted use of updrafts and gusts. In flight between trees, the species often falls into a woodpecker-like , wave-like flight, in which it alternately flaps its wings quickly and then puts them back close to the body. The pine jay often manages to descend great heights in a nosedive, plunging down from a control room and then suddenly braking with outstretched wings shortly before reaching its destination. Windy weather is often used by couples or groups for acrobatic maneuvers with swoops and circles.
Vocalizations
The pine jay does not have any real singing, but rather a subsong and a repertoire of eight to 13 individual calls. The fundamental frequency is between 1.2 and 3.4 kHz , the overtones between 5 and 7 kHz. The loud, rough call consists of three quick, consecutive kraak or kraa . Each syllable is 0.12–0.48 s long, the entire series takes an average of 2.4 s. The pine jay mainly uses this call in flight or when no conspecifics are in sight. The contact call is similar to the basic call, but is more stretched (0.12-0.48 s) and is uttered in shorter series (one or two calls in 2.4 s). Both calls can be heard about 1 km away.
The alarm call is a modified version of these two calls. The syllables are shorter here (0.22–0.65 s) and can be heard in very quick succession (two to six calls in 2.4 s). The alarm call expresses excitement and is made in the presence of potential threats and the presence of other pine jays. In addition, the species also has a melodious, multiple inflected call with low frequency, which the breeding partners let out during pair formation and nest building and which is also uttered between other individuals with close ties. Often there is also a high-pitched miirk or mjiu , which can be heard all year round, especially from two pine jets waiting to sit . The pine jay also has a number of other, mostly monosyllabic and rarer calls.
Spreading and migrations
The pine jay lives in the western mountains of the North American continent. Its species area is largely determined by the distribution of pines ( Pinus spp.) With large, wingless seeds. In Canada it stretches from the east of the Coast Ranges over central British Columbia to the Rocky Mountains in southwest Alberta . From there it follows the course of the mountains to the southwest and south to the Sacramento Highlands of New Mexico . In Arizona, it encompasses the Colorado Plateau and extends across the Nevada part of the Basin and Range Province to the Sierra Nevada of California. In California the species area is highly fragmented: In the extreme southwest there are two smaller breeding populations, the south and the California long valley are spared. To the north of the long valley there is a population in the cascade chain that extends as far as Washington. To the east there are two smaller areas on the north-eastern edge of the long valley and in the Warner Mountains . The pine jay is absent in the Black Rock Desert in northwest Nevada, as is the lower-lying regions of Idaho , Oregon, and Washington. In northwest Washington it joins the Canadian occurrences in the cascade chain. At Cerro Potosí in Mexico there is a highly isolated but stable breeding population.
The pine jay is usually a resident bird that only migrates from subalpine zones to lower elevations in winter when the local pine species no longer produce cones. Under favorable circumstances this can only be done in November, under unfavorable circumstances as early as August. After the breeding season, the birds migrate back to the subalpine regions in late spring. As with the pine jay , there can be irruptive migratory movements towards late summer and early autumn when there is little food available. The pine jay migrates partly to the Piñon-Juniper lowlands, partly to the south and east, where they then hibernate. The easternmost records of the species are in western Ontario , central Manitoba , Pennsylvania as well as Illinois and Arkansas .
habitat
A characteristic feature of all habitats used by pine jays is a sufficient occurrence of large-seeded pine species ( Pinus spp.). The typical habitat of the species consists in montane and subalpine pine forests with large-seeded species. These are, on the one hand, typical Piñon Juniper societies made up of pinyon pines and juniper species ( Juniperus (Sabina) spp.), And on the other hand, more montane and subalpine societies with Jeffrey pines ( P. jeffreyi ) or flexible ones ( Pinus flexilis ) or White-stemmed pine ( P. albicaulis ). The forest communities used by the pine jay are usually open or semi-open and, in addition to the decisive pine species, mostly consist of other conifers, such as coastal firs ( Abies grandis ) or Douglas firs ( Pseudotsuga menziesii ).
The species makes special demands on the breeding habitat. In Canada and the northwestern United States, it is usually open, park-like, and is dominated by yellow pine ( Pinus ponderosa ). The vertical distribution ranges in British Columbia from 0 to 2600 m, in Alberta from 1000 to 3840 m. Preference is given to altitudes of 900–3700 m over the entire distribution area.
Way of life
nutrition
The main food consists of seeds . When there is a shortage of seeds, insects , nuts , fruits , berries , eggs and small mammals are also eaten. Under the tongue is a kind of bag with which it can transport the seeds that it collects on pine trees over longer flight distances. It can also hold seeds in its beak. Like the squirrels, it hides most of the seeds in the ground for times of need throughout the year and has an amazing memory for retrieval, as laboratory studies have shown. Some biologists believe that certain pine trees rely on and depend on the pine jay to distribute their seeds. The seeds can therefore not be moved on their own, but must be moved by these animals!
Reproduction and breeding
In the case of the pine jay, both males and females participate in the breeding business. The clutch consists of two to four (sometimes six) eggs, which are hatched in a period of 16 to 18 days. After three weeks, the young leave the nest and stay for several months with the old animals, where they learn to collect and hide the seeds.
Sources and References
literature
- Josep del Hoyo, Andrew Elliot, David Christie (Eds.): Handbook of the Birds of the World. Volume 14: Bush-shrikes To Old World Sparrows. Lynx Edicions, Barcelona 2009, ISBN 9788496553507 .
- Urs N. Glutz von Blotzheim , KM Bauer : Handbook of the birds of Central Europe. Volume 13 / III: Passeriformes. 4th part. AULA-Verlag, Wiesbaden 1993, ISBN 3-89104-460-7 .
- Derek Goodwin: Crows of the World. 2nd Edition. The British Museum of Natural History , London 1986, ISBN 0565009796 .
- Steve Madge , Hilary Burn: Crows & Jays. Princeton University Press, Princeton 1994, ISBN 0-691-08883-7 .
Web links
- Diana F. Tomback: Clark's Nutcracker (Nucifraga columbiana) . In: A. Poole: The Birds of North America Online . Cornell Lab of Ornithology, Ithaca 1998, doi : 10.2173 / bna.331 .
- Nucifraga columbiana in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 30 of 2009.
- Videos, photos and sound recordings of Nucifraga columbiana in the Internet Bird Collection
Individual evidence
- ↑ a b Madge & Burn 1994 , p. 131.
- ↑ a b c d e f g h Tomback 1998 . Retrieved March 9, 2012.
- ↑ a b del Hoyo et al. 2009 , p. 612.