Tannenschnäppertyrann

Bestimmung

Adults are 12–14 cm long (4.7-5.5 in), span about 22 cm (8.7 in) across the wing and weigh 8-12 g (0.3-04 oz). They have grayish-olive upperparts, darker on the wings and tail, with whitish underparts; they have a conspicuous white eye ring, white wing bars, a small bill and a short tail. The breast is washed with grey and the sides of the belly with yellow. Females usually have a shorter, wider bill than males. Immature birds are similar to adults, but have broader wing bars and are more buff.<p>Many species of Empidonax flycatchers are very similar in appearance. Hammond's flycatchers are mainly confused with Dusky (E. oberholseri) and Gray (E. wrightii) flycatchers, which are similar in color and size and have an overlapping range. The best way to distinguish Hammond's flycatcher is by its call, breeding habitat and/or range.

Taxonomie

Hammond's flycatchers are part of the genus Empidonax, which includes a dozen of other species. Despite the relatively large range of the species, Hammond's flycatcher does not present a lot of genetic variations. This might be the result of a bottleneck event, that could have occurred when the species range was confined to the South of the Pleistocene ice. The bird's morphology, including its plumage, is also consistent across its range. However, there is evidence showing that some Hammond's flycatchers on Vancouver Island, in British Columbia, have evolved longer, thicker bills in the absence of Western flycatchers, which occupy a very similar niche, but usually have a thicker bill than Hammond's flycatcher. Hammond's, the Dusky and the Gray flycatchers are sister species, with no evidence of interbreeding.

Wissenschaftlicher Name

Empidonax hammondii

Autorität

(Xántus, J, 1858)

Ordnung

Passeriformes

Familie

Tyrannidae

Gattung

Empidonax

Verbreitung und Lebensraum

Hammond's flycatcher is a migratory species, breeding in Western North America and wintering in Mexico and Central America.<p>Their preferred breeding habitats are mature coniferous and mixed forests. They are typically found in dense fir forests, conifer and aspen forests and dogwood. Their wintering ground habitats are similar to those used as breeding grounds.<p>Hammond's flycatchers can be found in the Western United States, including Montana, Wyoming, California, Nevada, Utah, Arizona, New Mexico and Colorado. In Canada, their range includes British Columbia, Yukon and Alberta. Certain birds have been found as far north as Alaska. Overall, their breeding range is formed by regions that have been greatly influenced by past glaciation events. These birds are migratory and winter in Mexico and in Central America.

Brutgebiet

NA : c Alaska through w Canada to w USA

Überwinterungsgebiet

sw USA to Honduras

Zugverhalten

Vollzieher

Verhalten

Zugverhalten: Vollzieher.

Schutzstatus

Bestandstrend: zunehmend.

Bestandstrend

zunehmend