E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Catharus guttatus (Pallas, 1811)
Hermit Thrush
Family: Turdidae

Species account author: Jamie Fenneman
Photo of species

© Tim Zurowski  Email the photographer   (Photo ID #11769)


Distribution of Catharus guttatus in British Columbia.
(Click on the map to view a larger version.)
Source: Distribution map provided by Jamie Fenneman for E-Fauna BC

Species Information

Adult
The back, scapulars, and wings are medium brown, often washed with greyish or olive (depending on subspecies), and contrasting with the rufous-brown rump, uppertail coverts, and tail; the primaries often show a slight rufous tinge, especially on northern/boreal birds; and all subspecies show a prominent buffy bar across the base of the flight feathers on the underwing that is visible in flight. The underparts are whitish with a buffy-brown to olive grey wash on the sides and flanks and bold blackish or dark brown spotting on the breast that fades to paler greyish or olive spotting on the upper belly and sides in most individuals; the breast and sides are faintly washed with buff in many individuals, particularly on the Pacific coast and in the northern parts of the province. The head is brownish or greyish-brown (similar in colour to the remainder of the upperparts), with buffy lores and a buffy-white moustachial stripe that is separated from the whitish chin and throat by a narrow, but prominent, blackish malar stripe. There is a narrow complete whitish to buffy-white eye-ring. The iris is dark, the short, stout, pointed bill is dark brown or blackish with a horn-coloured or flesh-pink base to the lower mandible, and the legs and feet are flesh-pink.

First-winter immature
This plumage is acquired in late summer and is retained through fall migration. It is very similar to the adult, but is distinguished by the small buffy tips to the greater upperwing coverts that form a relatively inconspicuous pale wing bar.

Juvenile
Birds retain this plumage into the late summer of their first year, but molt prior to fall migration. It is similar to the plumage of the adult, but the head, upperparts, and upperwing coverts are finely but heavily spotted and streaked with buff, and the underparts have heavier and more extensive dark spotting (extending onto the belly).

Measurements
Total Length: 16.5-17.5 cm
Mass: 23-37 g

Source: Jones and Donovan (1996); Sibley (2000)

Biology

Identification

Identification of Catharus thrushes (Hermit, Swainson’s, and Gray-cheeked Thrushes, and Veery) is often very challenging, particularly if confronted with non-vocal birds during migration. Fortunately, the Hermit Thrush is relatively distinctive amongst this group of otherwise drab, skulking birds. It is most easily distinguished from all other Catharus thrushes by the rufous rump and tail that contrasts noticeably with the brownish to greyish-brown remainder of the upperparts and head. This feature is most prominent in the subspecies inhabiting the mountains of the southern interior (auduboni) as it has the palest and greyest upperparts of any of the subspecies; it is least noticeable on northern/boreal birds (faxoni), as they can often have a slight rufous tinge to the upperparts that obscures some of the contrast. Nonetheless, this feature is still moderately to strongly obvious on all birds and is not shown by any other Catharus thrush. In addition to the contrasting rump and tail, note the relatively bold, dark spotting on the breast of the Hermit Thrush; this spotting tends to be somewhat less boldly marked on other thrush species and/or the background colour of the breast is more strongly washed with buff and is not as clean and white. The presence of a relatively bold (although thin), white to buffy-white eye-ring is also a diagnostic feature that is not shown by the other thrushes. Tthe Swainson’s Thrush shows a buffy eye-ring, but this combines with the buff lores to form a ‘spectacled’ appearance that is not shown by the Hermit Thrush.

Finally, the Hermit Thrush also provides some additional behavioural clues that can help separate it from the other Catharus thrushes. It is often less skulky than the other species, and more often forages in open habitats (lawns, gardens, etc.), although it rarely strays far from at least some form of dense cover. When foraging, the Hermit Thrush characteristically cocks and flicks its tail and flicks its wings; this behaviour is shown rarely by other thrush species.
Vocalizations

The soft, ethereal, flute-like song begins with a single long, clear, whistled note that is followed by several higher twirling phrases that fade towards the end; successive songs often differ in pitch and overall tonal trend (rising or falling). The song of Pacific coast birds (guttatus, nanus) is slightly higher-pitched, harsher, and more mechanical-sounding, often with a downslurred and buzzy introductory note, while the song of northern/boreal (faxoni) and interior (auduboni) birds is somewhat purer and more liquid-sounding. Calls include a low, soft, dry chup or chuck (slightly higher and sharper in Pacific coast and interior birds than in northern/boreal birds), and a rising, whining zweeeee. The flight call is a clear, plaintive, whistled peew.

Source: Jones and Donovan (1996); Sibley (2000)

Breeding Ecology

Courtship
Males arrive on breeding grounds earlier than females so that territories are fully established by the time the females arrive. Courtship flights, in which the male chases the female around the territory in a rougly circular pattern, are an important component of the courtship process in this species. As the process of pair formation progresses, these flights become slower and more deliberate, with the pair often stopping occasionally and remaining motionless for several seconds before resuming the chase. Courtship chasing between the pair lasts 3-4 days, after which the male accepts the female on his territory and breeding commences.

Nest
The female alone constructs the nest over a period of 7-10 following the establishment of the pair bond. The nest is a neatly constructed, compact, bulky cup of grasses, leaves, moss, twigs, strips of bark, conifer needles, plant stalks, rootlets, hair, mud, and lichens; it is lined with finer materials such as small conifer needles, fine rootlets, fine grasses, hair, moss, strips of bark, and willow catkins. The nest is 10-15 cm in diameter and 5-8 cm in depth, with the internal cup 6-7 cm wide and 3.5-5.5 cm deep. The nest is typically placed at low levels (height usually <3 m, rarely to 6 m) among conifer branches or on the ground adjacent to the bases of trees or snags, in crevices, or under fallen logs, although some are occasionally constructed in deciduous shrubs.

Eggs
A clutch of (3) 4 (6) eggs is laid between late April and mid-July, with most egg-laying in the province occurring during June. The smooth, glossy, light blue to greenish-blue eggs, which are occasionally lightly flecked with brown speckles or spots, are incubated by the female for 11-13 days before hatching. Eggs occur in B.C. between late April and late July. The Hermit Thrush is an infrequent, but regular, host for nest parasitism by the Brown-headed Cowbird.

Young
The young are fully altricial and downy upon hatching, with dark flesh-pink skin and patches of dark grey down on the head, wings, and lower back; the mouth is orange-yellow and the gap flanges are yellow. The nestlings are tended by both parents for (10) 12-13 (15) days before fledging and leaving the nest. After fledging, the young are tended to by the adults for an unknown period of time before dispersing and becoming fully independent. Nestlings and dependent fledglings occuir in B.C. between mid-May and late August, with most present in the province between mid-June and late July.

Source: Jones and Donovan (1996); Baicich and Harrison (1997); Campbell et al. (1997) 
Foraging Ecology

The Hermit Thrush feeds primarily on invertebrates and fruits, with insects and other small invertebrates (spiders, etc.) dominating the diet during the breeding season and berries and other small fruits becoming more important during the fall and winter (where they are available). In the absence of berries and fruits in winter, this species continues to rely heavily on invertebrate prey. There are rare reports of Hermit Thrush killing and consuming small vertebrates, such as small frogs and reptiles, but this is considerably infrequent and invertebrates are by far the dominant animal prey.

Individuals often forage within dense cover, regularly occurring throughout the forest interior, although they will also venture away from cover into more open habitats for foraging, provided that dense escape cover remains nearby. Most foraging is ground-based, during which the bird moves using characteristic robin-like hops, but it will also glean food items from the lower levels (<3 m height) of brushy and forested habitat (rarely occurring into the subcanopy or even canopy). When foraging, the Hermit Thrush scans the ground or branch visually, often flicking aside vegetation to expose prey hiding underneath. It will also engage in short aerial sallies or bouts of hovering in order to pursue flying insect prey or to inspect vegetation where it is not able to secure a solid footing.

Source: Jones and Donovan (1996)

Habitat


This species is closely associated with coniferous, and to a lesser extent, mixed forests throughout its breeding range. It is a characteristic species of montane and subalpine spruce-fir forests across the southern interior, commonly ranging into patches of krummholz vegetation at and above treeline elevations. On the coast, this species typically occurs in montane and subalpine forests of fir, mountain hemlock, and yellow-cedar, but also ranges locally down into coniferous forests at or near sea level along the outer coast (especially along the northern coast and on the Queen Charlotte Islands). In the central and, especially, northeastern parts of the interior, the Hermit Thrush is characteristic of mixed, and even deciduous, forest stands, although it also regularly occurs in pure coniferous forests. Throughout its breeding range, it is most abundant in moist to mesic forests and riparian habitats with a dense shrubby understory (including the edges of beaver ponds, bogs, lakeshore thickets, and forested swamps), especially where berry-producing shrubs are plentiful, and occurs both along forest edges as well as within the forest interior. Wintering birds on the south coast are most common in mature and second-growth coniferous forests, but also occur in low densities in younger forests and other brushy habitats; wintering birds are also sometimes observed in suburban parks and gardens, especially where berry-producing shrubs are present. Spring and fall migrants are found in a wide variety of brushy and forested habitats, although they tend to prefer areas of dense cover (brushy forest edges, hedgerows, powerline rights-of-way, parks, etc.).

Source: Campbell et al. (1997)

Distribution

Global Range

Breeds across northern North America, from Alaska east to Newfoundland, as well as south through western Canada and the western United States to southern California, Arizona, and New Mexico and south through the Appalachians (eastern United States) to Virginia. Winters along the Pacific coast north to southwestern B.C., as well as across the southern and eastern United States (north to Arizona, New Mexico, Nebraska, Pennsylvania, and New York) and throughout Mexico and northern Central America (Guatemala).
BC Distribution

Breeding
Common throughout all of B.C., including all coastal islands (Queen Charlotte Islands, Vancouver Island, etc.). Primarily restricted to upper elevations across southern portions of the province, and thus largely absent from the dry interior valleys and the Georgia depression.

Winter
Generally rare to uncommon on Vancouver Island and the southern mainland coast (Lower Mainland, Sunshine Coast), although it can be locally fairly common along the outer coast of Vancouver Island and locally in some of the forested valleys on northern parts of the island. Very rare in winter on the Queen Charlotte Islands, as well as in the southern Okanagan Valley of the south-central interior. Casual farther north in the interior in winter, with the northernmost winter record from Williams Lake.

Migration and Vagrancy
Fairly common to common spring and fall migrant throughout all of British Columbia, including all offshore islands. Populations breeding in northern B.C. (especially those east of the Rockies) follow a different (easterly) migration path from those breeding elsewhere across the province, and therefore tend to arrive slightly later in the spring and depart earlier in the fall.

The first spring migrants begin moving north through the south coast in late March and early April, although some of the earliest arrivals may be difficult to separate from overwintering birds. Peak northward movement along the coast occurs between mid-April and early May, with the latest spring migrants moving through the region in late May or early June. Farther north along the coast (e.g., Queen Charlotte Islands), spring migrants do not begin to appear until mid- to late April, with peak movements occurring during the latter half of May and early June. In the southern interior, the first spring migrants arrive in the Okanagan Valley in early April and elsewhere across the southern interior in late April or early May; peak northward movements across the southern interior occur during May. The first spring migrants do not reach the central and northern interior until early May (exceptionally late April), with peak movements occurring between mid-May and early June.

The first southward-bound fall migrants depart the breeding grounds in northern B.C. in mid-July, with numbers declining rapidly through late July and early August; most individuals have departed northern B.C. by late August, with exceptional individuals lingering into early September. In central B.C., most southward movement occurs during August and September, with occasional birds lingering into early or even mid-October. Across the southern interior, fall migration occurs primarily during August and September (slightly later in the Okanagan Valley), with the latest individuals lingering in the southern valleys into October or even November. On the coast, most southward-bound fall movement occurs during September and October, with peak movements occurring between late September and mid-October. Small numbers continue to move through the coast (primarily the south coast) in November and early December, with the latter birds difficult to discern from overwintering individuals.

Source: Campbell et al. (1997)

Conservation

Population and Conservation Status

This is a common and widespread species throughout B.C., and is not recognized as a species of concern at either the federal (COSEWIC [Committee on the Status of Endangered Wildlife in Canada] or provincial (BC CDC [Conservation Data Centre]) levels.

Taxonomy


The Hermit Thrush is one of the most geographically variable species in North America. Although 13 or more subspecies have been recognized for North America by some authors (e.g., Pyle, 1997), several of these have been incoporated into more broadly-defined subspecies by other authors (e.g., Jones and Donovan, 1996); the latter authors describe only 8 subspecies. The subspecies are grouped into three relatively well-defined subspecies groups, including a smaller and browner Pacific coastal group (three subspecies), a larger and greyer interior mountain group (three subspecies), and a mid-sized and brighter boreal/eastern group (two subspecies). British Columbia breeding populations include representatives of each of these three subspecies groups.

Based on the taxonomic classification of Jones and Donovan (1996), the following four subspecies occur in British Columbia:

Catharus guttatus guttatus
This subspecies, which is the most widespread and common member of the “Pacific coastal” subspecies group, breeds throughout most of the northwestern, central, and south-central interior of B.C. and winters sporadically on the southwest coast of the province. This subspecies is similar to C.g.nanus, but averages slightly larger, with paler brown upperparts, paler grey flanks, and slightly whiter underparts. Birds breeding in the southern interior that average slightly browner (less rufescent) have been called C.g.oromelas (Oberholser), while individuals breeding in the central interior that may average slightly larger and broader-billed than other populations have been designated C.g.munroi Phillips; neither of these subspecies is recognized here.

Catharus guttatus nanus (Audubon)
This subspecies, which is a member of the “Pacific coastal” subspecies group, breeds along the coast of British Columbia, including the Queen Charlotte Islands and Vancouver Island, and winters on Vancouver Island and the southern mainland coast. It is similar to the more widespread C.g.guttatus, but is smaller and darker, with darker grey flanks and a slightly buffier (on average) breast. Birds breeding on the Queen Charlotte Islands and Vancouver Island are somewhat darker brown on the upperparts than birds elsewhere in the subspecies’ breeding range, with heavier dark spotting and a stronger buff wash on the breast and paler grey flanks; these birds are sometimes separated as C.g.vaccinius (Cumming).

Catharus guttatus auduboni (Baird)
This is the only member of the “interior mountain” subspecies group in British Columbia. It breeds throughout the mountains of the southeastern interior. It is larger and paler than other subspecies in B.C., with a greyer head and upperparts and a brighter, more strongly contrasting rufous rump and tail; the whiter underparts are more boldly spotted with larger, blacker spots.

Catharus guttatus faxoni (Bangs and Penard)
This is the only provincial representative of the “boreal/eastern” subspecies group. It breeds throughout northeastern B.C. east of the Rocky Mountains, as well as throughout the Liard Basin and other areas of northern B.C. south of the Yukon border. This subspecies is somewhat similar to the Pacific coastal subspecies (C.g.guttatus, C.g.nanus), but is more rufous-tinged on the upperparts, has a heavy buff wash on the flanks, and has less strongly contrasting dark spots on the buffy-white breast which fade to greyish towards the belly.

Source: Jones and Donovan (1996); Pyle (1997)

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
NativeS5BYellowNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Range and Status Information Links

Additional Photo Sources

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-06-14 5:29:56 PM]
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