Adult The upperparts (back, scapulars, rump, uppertail coverts) are wholly dull olive-green, with a slightly brighter and greener rump. The wings are dark dusky-grey with thin yellow edges on the primaries, secondaries, and primary coverts, thin pale yellowish-olive or dull whitish edges on the tertials, and pale yellowish-olive to pale olive-buff (sometimes almost whitish) tips on the greater and median wing coverts, forming two distinct pale wing bars. The slender, shallowly notched tail is dark dusky-grey with thin yellow outer edges on the feathers. The underparts are pale olive-buff with a darker olive wash on the sides and flanks. The head is dull olive-green (similar to the upperparts), with a paler olive-buff throat and sides of the neck (palest on the throat). The lores are dull yellowish-olive and there is an incomplete pale yellowish-olive eye-ring that is thickest behind the eye and broken above the eye. The iris is dark, the stout, pointed bill is dark grey (darker on the upper mandible), and the legs and feet are dark bluish-grey.
Juvenile This plumage is held into the late summer (August) of the first year. It is very similar to the plumage of the adult, but is duller and browner, with darker buffy-olive to dull brownish wing bars.
Measurements Total Length: 12.5-13 cm Mass: 9-15 g
Hutton’s Vireo is reasonably distinct from other vireo species in B.C. and is easily distinguished from the most similar member of this group, the Cassin’s Vireo, by its smaller size, lack of bold white ‘spectacles’ on the face (Hutton’s Vireo has much duller, olive-tinged ‘spectacles’ that are broken above the eye) and overall duller and greener plumage, especially on the throat and underparts. Cassin’s Vireo has a whiter throat and underparts and is often tinged with grey on the head.
Hutton’s Vireo is very similar to the Ruby-crowned Kinglet, and this similarity likely accounts for occasional reports of Hutton’s Vireo in south-central B.C. outside of the expected range of the species. Differences in structure and behaviour, although subtle and requiring experience with both species to be valuable, are often helpful in differentiating these two species before the minor differences in plumage can be assessed. Hutton’s Vireo is a slightly (but noticeably) larger and bulkier species and has a distinctly thicker bill than Ruby-crowned Kinglet (which has a very fine, sharp bill). Hutton’s Vireo moves and forages in typical vireo fashion, moving relatively slowly and deliberately among the foliage and branches, whereas Ruby-crowned Kinglet is much more active, regularly flitting among the outer twigs and foliage and often hovering momentarily at branch tips in search of insects (this behaviour is only occasionally shown by Hutton’s Vireo). The most important plumage characteristic to note when separating these two species is the presence of a thick black bar on the wing of Ruby-crowned Kinglet. This bar is along the base of the secondaries and immediately below the lower of the two white wing bars. Hutton’s Vireo, in contrast, shows no such black bar and has only the two whitish wing bars. An additional field mark of Hutton’s Vireo is the more noticeable pale lores which, when combined with the pale eye-ring, give the bird the impression of having ‘spectacles.’ Ruby-crowned Kinglet has duller, greener lores and a brighter, whiter eye-ring so that it does not typically show the suggestion of ‘spectacles.’
The song of the male is a variable, monotonous series of burry, nasal, one- or two-note calls that are often repeated at a rate of ~1 phrase per second for a period of up to 10 minutes. One commonly-heard variation of this song include a series of two-part notes with the second note higher-pitched: zu-weep...zu-weep....zu-weep…zu-weep…zu-weep… Another commonly-heard variation of this song is a series of descending, slurred notes: zweeer…zweeer....zweeer...zweeer…zweeer… Occasionally the male sings a monotonous series of flat, single-syllable phrases: chew…chew…chew…chew…chew… The most frequently produced call, especially during the winter, is a whinnying, chattering rheeee-he-he-he-he-he with a distinctive laughter-like quality; in some situations, only the raspy, ascending rheeeee portion of this call is given. Also gives a short, dry pik or chit and a high, harsh, mewing sshhhhrrii shhhri shhr shhr.
Courtship Courtship and pair formation occurs very early in the year, often as early as February or March. Some pair bonds may be retained throughout the year, as evidenced by observations of apparent pairs at all seasons. Courtship in this species primarily involves song, during which time the male sings for prolonged periods from an unexposed perch within the canopy. The male often moves about the branches while singing, sometimes even foraging between phrases. The female solicits copulation by crouching on a branch and fluttering her wings. Later in the season, the male sometimes sings from the nest while incubating the eggs.
Nest Nest construction begins early, with some pairs beginning in late February or early March concurrent with the start of courtship. Both sexes participate in the construction of the nest over a period of 3-14 days (longer during prolonged periods of rain). The nest is usually placed near the end of a horizontal branch, where it is suspended from a fork in the branch and is usually well-hidden by overhanging foliage. Nest heights range from (1) 3-12 (15) m. The nest itself is a deep, rounded or somewhat globular hanging cup 7.6-8.3 cm wide and ~7 cm deep. It is composed of a wide variety of materials such as fine grasses, moss, lichens, small leaves, plant down, moth and spider cocoons, spider silk, feathers, and shreds of bark; moss is the most important construction material for nests in B.C. It is generally lined with fine grasses as well as smaller amounts of hair, feathers, and fine shreds of bark.
Eggs A clutch of (1) 3-4 (5) eggs is laid within several days of the completion of the nest, usually in early spring (mid-March through April), and hatches 14-16 days later. Both sexes incubate the eggs. This species appears to be double-brooded, and presumed second clutches in B.C. have been recorded from May through June. The smooth, moderately glossy eggs are white and very sparsely marked with a few brown or reddish-brown specks or spots at the larger end (occasionally unmarked). The Hutton’s Vireo is an infrequent host for Brown-headed Cowbird parasitism, and several instances of such parasitism have been noted in B.C.
Young The nestlings are altricial and naked upon hatching, with flesh-coloured or pinkish skin, but quickly develop pale yellowish-white to pinkish-white or very pale grey down. Both parents tend to the young throughout the nestling period, including brooding. The young leave the nest at 14-17 days of age and are subsequently tended by both adults for up to 3 weeks before becoming independent. Nestlings and dependent young are present in B.C. between early April and late July.
Source: Baicich and Harrison (1997); Campbell et al. (1997); Davis (2005)
Most foraging activity takes place in the mid to upper canopy of coniferous or, less frequently, deciduous trees, often in the outer portions of the branches but generally not fully exposed. It sometimes descends to lower levels, occasionally moving into understory vegetation or even shrubby areas adjacent to mature trees. This species primarily consumes invertebrate prey, particularly insects and their larvae, which it gleans from the surfaces of branches, bark, leaves, flowers, and fruits. It sometimes hovers momentarily to glean prey or pursues aerial prey during short flights. Many prey items are captured by flying rapidly towards a branch or other surface and snatching the prey, then returning to a perch to consume it. Small berries (elderberries, etc.) are occasionally consumed when they are available, and this species has been known to drink sap oozing from holes created by the Red-breasted Sapsucker. Outside of the breeding season, the Hutton’s Vireo commonly travels with mixed-species feeding assemblages alongside chickadees, kinglets, nuthatches, and Brown Creeper. It is difficult to detect in these flocks, however, due to its quiet and retiring nature and tendency to occur as only one or two individuals per flock.
Source: Davis (1995)
This species is most characteristic of second-growth, mature, and old-growth coniferous and mixed forests throughout the year, and is one of few species that regularly occur in the vast, monotonous, species-poor stands of regenerating Douglas-fir on the south coast. It occurs in association with a wide variety of tree species, including species such as Garry Oak, Arbutus, and Lodgepole Pine that are commonly found in drier areas. It also regularly inhabits brushy forest edges, riparian thickets, and even well-treed suburbs and parks, especially outside of the breeding season, but is rarely found far from at least some coniferous trees even at this time of year. Unlike populations farther south along the Pacific coast of the United States, populations in B.C. do not appear to be particularly strongly associated with oak forests and, instead, show a strong affinity for coniferous trees.
Source: Campbell et al. (1997)
Resident along the Pacific coast of North America, from southwestern B.C. south to northern Baja California, Mexico. A separate population also ranges from the southwestern United States (Arizona, New Mexico, Texas) south through the highlands of Mexico to Guatemala.
Resident Uncommon to fairly common at lower elevations throughout Vancouver Island, the Gulf Islands, and the southern mainland coast of the province north to Rivers Inlet. It ranges inland into the lower slopes of the Coast and Cascade Mountains as well as along the Fraser River as far as Hope and Manning Provincial Park. It is non-migratory, but some birds tend to wander in the late summer and fall and can appear in areas where the species is not normally detected (such as at elevations above those normally occupied by the species). This species is generally more common than records suggest due to its quiet and retiring nature throughout much of the year, especially during the winter and in mid-summer when it is particularly difficult to detect.
Source: Campbell et al. (1997)
Population and Conservation Status
The range of the Hutton’s Vireo in B.C. is closely correlated with areas of the province that are subject to very high rates of urban and agricultural development as well as forest harvesting activities, and as such the species would be expected to be a candidate for population declines. However, it appears that the species adapts well to managed forests and is able to exist in second-growth monocultures of Douglas-fir and other conifers that otherwise support very low density and diversity of bird species. As well, it is able to successfully breed in suburban areas as long as sufficient stands of coniferous trees remain in parks and gardens. Although it has undoubtedly been lost from some of the more urbanized environments of the Lower Mainland and Vancouver Island, populations elsewhere seem to be stable and persistent. As a result, the species is not recognized by either the B.C. Conservation Data Centre (CDC) or COSEWIC (Committee on the Status of Endangered Wildlife in Canada) as a species of conservation concern.
Two disjunct populations, one occurring along the Pacific coast and the other in the southwestern United States, Mexico, and Guatemala, are reproductively isolated from each other and may represent distinct species. A total of seven subspecies of V.huttoni are recognized, with four of these occurring north of Mexico and two in British Columbia.
The subspecies that occur in British Columbia are as follows:
Vireo huttoni huttoni This subspecies ranges along the Pacific coast from southwestern B.C. to northern Baja California, Mexico. It is very similar to V.h.insularis but averages slightly duller.
Vireo huttoni insularis Rhoades This subspecies is endemic to Vancouver Island. It is very similar to V.h.huttoni, which inhabits nearby areas of the adjacent mainland, but has a slightly richer and brighter plumage with darker, greener-tinged upperparts and slightly more yellow-tinged underparts. The differences between these subspecies are extremely subtle and not likely noticeable in the field, and some authors (e.g., Pyle ) include insularis within huttoni.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. 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:
16/09/2019 3:32:35 PM]
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