MacGillivray's Warbler
Geothlypis tolmiei
Summary 7
The MacGillivray's warbler (Geothlypis tolmiei) is a small species of New World warbler. These birds are sluggish and heavy warblers with short tails, preferring to spend most of their time on, or near the ground, except when singing.
Distribution 8
MacGillivray’s warblers breed in western North America as far north as southeastern Alaska and as far south as Central Arizona and parts of southern California. There have been records of them nesting as far east as the Cypress Hills of South Dakota, but they are more commonly found in the Rocky Mountains and west to the Pacific Ocean. MacGillivray’s warblers winter primarily along the pacific slope of Central America from north Mexico to Panama, though they occur as far south as Colombia. Some birds have been known to over winter as far north as southern California (San Diego), but this is quite rare.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Morphology 9
MacGillivray’s warblers are small warblers, weighing between 8.6 and 12.6 grams (mean 10.4 g). They are 10 to 15 cm long with an average wingspan of 7.5 cm. Adult males in alternate plumage exhibit a broken eye ring, jet black hood, yellow underparts, distinctive black lores, and an olive back. There is considerable sexual dimorphism, as females’ hoods are always a light grey with a whitish chin. Juvenile birds appear similar to adult females, but may show slight black lores. Similar species include both mourning warblers (Oporornis philadelphia) and Connecticut warblers (Oporornis agilis). Though the broken eye-ring is usually diagnostic, mourning Warblers may have a thin broken eye-ring. For definitive identification, a wing length minus tail length value of less than 10 mm will distinguish MacGillivray's warblers from mourning warblers (wing-tail > 19mm).
Range mass: 8.6 to 12.6 g.
Average mass: 10.4 g.
Range length: 10 to 15 cm.
Average wingspan: 7.5 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Habitat 10
MacGillivray’s warblers breed primarily at moderate elevations (up to 3000 m) in secondary growth coniferous forests and riparian corridors. In the north parts of their range they inhabit some deciduous forests and will sometimes breed in chaparral. During migration, they are found in dense shrubs in mountain ranges. In their wintering range, they are generally encountered in humid or semiarid second growth forest.
Range elevation: 3000 (high) m.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: chaparral ; forest ; rainforest ; scrub forest
Other Habitat Features: riparian
Migration 11
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.
Migrants arrive in southern winter range mid-September, depart by mid-May (Stiles and Skutch 1989).
Sources and Credits
- (c) Matt Ewalt, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/94942458@N00/167212990
- (c) Bryant, some rights reserved (CC BY-NC), http://farm4.static.flickr.com/3644/3650879839_86a1b311cd.jpg
- (c) Donna Pomeroy, some rights reserved (CC BY-NC), uploaded by Donna Pomeroy
- (c) Andrea Cantú, some rights reserved (CC BY-NC), uploaded by Andrea Cantú
- (c) Javier Salgado, some rights reserved (CC BY-NC), uploaded by Javier Salgado
- (c) Ken-ichi Ueda, some rights reserved (CC BY-NC-SA), http://farm5.static.flickr.com/4134/4770101531_7159745ccc_b.jpg
- (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Geothlypis_tolmiei
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31411567
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31411569
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31411568
- (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28864435
