Gray-cheeked thrush
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The gray-cheeked thrush (Catharus minimus) is a medium-sized thrush. This species is Template:Cvt in length, and has the white-dark-white underwing pattern characteristic of Catharus thrushes. It is a member of a close-knit group of migrant species together with the veery and Bicknell's thrush;<ref name="Winker" /> it forms a cryptic species pair with the latter. The gray-cheeked thrush is all but indistinguishable from Bicknell's thrush except by its slightly larger size and different song. The two were formerly considered conspecific.<ref name=":0">Template:Cite journal</ref> Of all the American spotted thrushes, the gray-cheeked has the most northern breeding range.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
DescriptionEdit
The gray-cheeked thrush is slightly larger than other Catharus thrushes, about 16 to Template:Cvt in height and weighing between 26 and 30g.<ref name=":1">Template:Cite news</ref> Wingspan ranges from 12.6-13.4 in (32-34 cm).<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The bird can be identified by its grayish face, partial pale eyering, drab gray-brown upperside and extensively dusky flanks.<ref name=":2">Template:Cite book</ref> The area between the eye and the beak is grayish as well, but the area running from the beak to above the eye is grayish white.<ref name=":1" /> The gray-cheeked thrush is nearly identical to the Bicknell's Thrush.<ref name=":2" />
There are two subspecies: the northern gray-cheeked thrush (Catharus minimus alicia), and the nominate subspecies, the Newfoundland gray-cheeked thrush (C. m. minimus).<ref name=":3">Template:Cite journal</ref> C. m. minimus can be distinguished by its overall browner coloration and buffer wash to the breast compared to C. m. alicia.<ref name=":3" /> C. m. minimus also has an extensive brighter yellow area at the base of the lower part of the beak.<ref name=":3" /> C. m. alicia has a grayish olive upperpart (whereas C. m. minimus has a brownish olive upperpart<ref>Template:Cite book</ref>) and flanks, a lightly washed cream breast and duller lower part of the beak.<ref name=":1" />
TaxonomyEdit
In addition to being almost identical physically, the gray-cheeked thrush is sister species to the Bicknell's thrush (Catharus bicknelli). The divergence of the two species is very recent<ref name=":0" /> since only little genetic divergence separate them.<ref name=":1" /> Dr. Henri Ouellet was the first to propose the separation between the Bicknell's and the gray-cheeked thrush in 1996.<ref>Template:Cite journal</ref>
Habitat and distributionEdit
The gray-cheeked thrush is a long-distance migrant species with a migration on average of 300 km.<ref name=":1" /> They are believed to spend their winter in the Amazon basin and will cross the Caribbean Sea and Gulf of Mexico during their spring migration.<ref>Template:Cite journal</ref>
They are present in their breeding ground from May to August.<ref name=":1" /> They breeding range includes the northern boreal forests from Newfoundland to Alaska in North America and across the Bering Sea to Eastern Siberia associated with dense conifer and broadleaf shrub thickets.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> C. minimus remains uncommon to rare in most regions of North America but can be spotted in any wooded habitat.<ref name=":2" /> The breeding range extends north of the treeline into low Arctic willow and alder beds.<ref name=":4">Template:Cite journal</ref> Grey-cheeked thrushes prefer low coniferous woods, including young regenerating forests, open canopy old growth forests having a dense growth of shrubs and small conifers in the understory, and dense, stunted spruce and fir on windblown sites and near the tree line.<ref name=":1" />
The subspecies of C. minimus are also separated by their different breeding ranges: C. m. alicia breeds from Labrador west to Siberia, and C. m. minimus breeds on the island of Newfoundland and possibly adjacent portions of southern coastal Labrador.<ref name=":3" />
BehaviorEdit
VocalizationsEdit
The vocalizations of the gray-cheeked thrush are the most reliable way to identify it, compared to the Bicknell's Thrush.<ref name=":2" /> It has a complex song of burry flute-like notes, usually inflecting downward at the end.<ref name=":5">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It resembles a descending spiral like the veery (Catharus fuscescens), but higher, thinner, and nasal with stuttering pauses: "ch-ch zreeew zi-zi-zreeee zizreeew".<ref name=":2" /> The flight call is a high, penetrating, nasal "queer".<ref name=":2" /> It is more likely to hear its nocturnal flight call during spring and fall migration than to observe the species on the ground.<ref name=":4" /> The nocturnal flight note a one or two note "whe-eer" dropping in pitch.<ref name=":5" />
DietEdit
C. minimus consumes mainly insects, such as beetles, weevils, ants, wasps, and caterpillars, in addition to arachnids as well as fruits and berries (wild cherries, blackberries, and raspberries).<ref name=":5" /><ref name=":1" /> It also feeds on crayfish, sow bugs, and earthworms.<ref name=":5" />
Their habits of eating berries contribute to the dispersion of seeds.<ref name=":5" />
ReproductionEdit
C. minimus exhibits secretive behaviour during breeding season, and nesting pairs are rarely found in high densities<ref name=":1" /> as their territories are well-spaced.<ref name=":0" /> They build their nests on the ground or in low shrubs, typically less than 2 meters high.<ref name=":4" /><ref name=":1" /> Females build the nest with dried grasses mixed with a supporting layer of mud.<ref name=":5" /> There is only one brood per season, although they will lay a second brood if the first nest fails early in the season.<ref name=":5" />
There is an average of 4 eggs per nest, but it may vary between 3 and 5 eggs. The female incubates the eggs for 13 to 14 days.<ref name=":5" /><ref name=":4" /><ref name=":1" /><ref name=":0" /> The eggs are greenish blue, marked with light brown dots and oval to short oval in shape.<ref name=":5" /> Nestlings fledge 11 to 13 days after hatching and the young are cared for by both parents.<ref name=":1" /> Individuals breed at one year of age and are presumed monogamous.<ref name=":1" />
ReferencesEdit
External linksEdit
- Gray-cheeked Thrush – Catharus minimus – USGS Patuxent Bird Identification InfoCenter
- Gray-cheeked Thrush Species Account – Cornell Lab of Ornithology