Mexican jay
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Mexican jay ( Aphelocoma wollweberi ) |
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| Aphelocoma wollweberi | ||||||||||||
| Kaup , 1854 |
The Mexican jays ( Aphelocoma wollweberi ), sometimes called Mexican Jays called, is a species from the family of corvids (Corvidae).
description
Appearance
The Mexican jay reaches a length of 29 centimeters and a weight between 105 and 144 grams. The head, top of wings and tail are bright blue. The back plumage is matt blue to bluish gray, the underside whitish gray. Iris beak and legs are black-brown to black in color. There is no sexual dimorphism .
Similar species
The island jay ( Aphelocoma insularis ) is distinguished by its dark gray colored shoulder wings and is found exclusively on Santa Cruz Island off the southern California coast.
distribution and habitat
The distribution area of the Mexican jay extends from the southern parts of the US states of Texas , New Mexico and Arizona to northern Mexico . It prefers to live in oak ( Quercus ) or mixed forests .
Way of life
The Mexican jays live together in groups. They primarily look for food on the ground. This consists largely of acorns, pine nuts and nuts, some of which are buried in the ground as a supply. It was observed how the jays shake peanuts before they crack in order to estimate their weight or their filling. In this way they found out how heavy and well-filled a nut is. If they seemed too easy, the birds spurned the food and thus saved the energy for cracking the nuts. The other food spectrum of the jays includes insects as well as berries , lizards and small snakes . Even the nests of small bird species are sometimes looted. But the black-chinned hummingbirds ( Archilochus alexandri ) , for example, have developed a strategy to protect their eggs and nestlings from predators: They nest where the hawks breed. Since the jays avoid the proximity of these birds of prey, the hummingbirds can raise their young undisturbed.
The nests of the Mexican jays are usually created in small colonies in tall trees. Four to five eggs are usually laid. These are pale green to blue-green in color and are sometimes covered with a few small gray-brown spots. The breeding season is around 18 days. The female breeds alone and is provided with food by members of the colony during this period. Both parents feed the nestlings, which fly out after 25 to 28 days and are then fed by the parents for some time.
Danger
The Mexican jay is not uncommon in its areas of distribution and is therefore classified by the IUCN as a 
“ least concern ”. It is protected by the United States Fish and Wildlife Service under the Migratory Bird Treaty Act .
Taxonomy and subspecies
The formerly known Mexican jay ( Aphelocoma ultramarina guided) type was in 2011 by decision of the American Ornithologists' Union Check-list of North American Birds split based on significant phenotypic differences in plumage and morphology, and genetic divergence in two distinct ways. After that, the populations living in the Transvolcanic Belt were listed as Transvolcanic jay ( Aphelocoma ultramarina ). The populations further north have been listed as Mexican jay since then , but with the scientific name Aphelocoma wollweberi .
The following subspecies are distinguished:
- Aphelocoma wollweberi arizonae ( Ridgway , 1874 )
- Aphelocoma wollweberi couchii ( Baird, SF , 1858 )
- Aphelocoma wollweberi gracilis Miller, GS , 1896
- Aphelocoma wollweberi potosina Nelson , 1899
- Aphelocoma wollweberi wollweberi Kaup, 1854
Some authors consider Aphelocoma potosina as a separate species. Further studies are necessary in this regard.
literature
- Johann Jakob Kaup: A few words about the systematic position of the raven family, Corvidae . In: Journal of Ornithology . tape 2 (separate issue), 1854, p. 48-56 ( biodiversitylibrary.org [accessed March 10, 2016]).
- Gerrit Smith Miller, Jr: Description of a New Jay from Mexico . In: The Auk . tape 13 , no. 1 , 1896, p. 34–37 ( sora.unm.edu [PDF; 141 kB ; accessed on March 10, 2016]).
- Edward William Nelson: Descriptions of New Birds from Mexico . In: The Auk . tape 16 , no. 1 , 1899, p. 25–31 ( sora.unm.edu [PDF; 266 kB ; accessed on March 10, 2016]).
- Robert Ridgway, Spencer Fullerton Baird: On some new forms of American birds . In: Bulletin of the Essex Institute . tape 5 , no. 12 , 1874, p. 197-201 ( biodiversitylibrary.org [accessed March 10, 2016] 1874 (1873)).
- Spencer Fullerton Baird: Birds . In: Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean. Made under the direction of the secretary of war, in 1853-6 . tape 5 , no. 12 , 1858, pp. 1–1005 ( biodiversitylibrary.org [accessed March 10, 2016]).
Individual evidence
- ↑ Distribution area
- ↑ Nut shaking trick
- ↑ Hummingbird Survival Strategy
- ^ Guide to North American Birds
- ^ IUCN Red List
- ^ Migratory Bird Treaty Act
- ↑ Chesser, R. Terry, Richard C. Banks, F. Keith Barker, Carla Cicero, Jon L. Dunn, Andrew W. Kratter, Irby J. Lovette, Pamela C. Rasmussen, JV Remsen, James D. Rising, Douglas F. Stotz, Kevin Winker: Fifty-second supplement to the American Ornithologists' Union Check-List of North American Birds. Auk 128 (3), The American Ornithologists' Union, 2011, pp. 600-613.
- ^ IOC World bird list Crows, mudnesters & birds-of-paradise
- ^ Robert Ridgway, p. 199.
- ^ Spencer Fullerton Baird, p. 588.
- ^ Gerrit Smith Miller, Jr, p. 34.
- ^ Edward William Nelson, p. 27.
- ↑ Johann Jakob Kaup, p. 55.
- ^ The Birds of North America
Web links
- Mexican jay (Aphelocoma wollweberi) in the Encyclopedia of Life . Retrieved August 11, 2017.