Hutton’s Vireo

The Hutton’s Vireo is an inconspicuous stocky vireo usually heard before it is seen. Its two part song is sung persistently. It is a year round resident, with some altitudinal and short distance migration from southern coastal British Columbia along the Pacific coast to southern California as well as southeast Arizona and southwest New Mexico south to central Guatemala in Central America.

Adult Male (spring/summer)

Upperparts are dull greenish olive to gray olive. Wing-bars are whitish to yellowish and outer vanes of the regimes and rectrices are edged greenish yellow to yellowish white. The underparts are dull yellowish white washed with pale buff to grayish olive. The pale whitish eye-ring is broken at the top. The lores are pale. The bill is thick and hooked, blackish above, paler below. The legs and toes are blue-gray to dark gray.

Adult Female (spring/summer)
Sexes are similar.

Juvenile
Similar to adults but wing bars are dull buffy yellow.

General:

Small stocky vireo that is sexually monomorphic. Length: 10-12cm. Wing: 20-21cm. Weight: 9-15g.

Behaviour:

The Hutton’s Vireo feeds mostly on insects and some seed berries by hopping from twig to twig. It often hovers momentarily to pick an insect from the foliage.

During winter Hutton’s Vireos often move through the forest with small flocks of other small birds such as kinglets, chickadees and nuthatches.

Individuals begin singing in late winter and begin nesting in early spring. Subsequently, they may be under-represented on breeding bird surveys and atlas projects, which begin after peak singing season for this species.

Habitat:

Seen in evergreen forests and woodlands with moderate to dense crown closure and understory.

Information:

The Hutton’s Vireo was given its name in 1851 by John Cassin for William Hutton a collector of field birds about whom little is known.

The courting male postures before the female, fluffs its feathers, fans its tail and gives a “whining” or “snarling” call.

These vireos construct hanging cup nests suspended by the rim in a fork of a twig or branch. The nest hangs far out on the limb of a 6 to 25 foot tall conifer tree. It is made of moss, lichen, and twigs and is lined with finer materials. Hutton’s Vireo lay 3 to 5, usually 4, eggs with brown spots mostly near the large end.

Similar species:

Ruby-crowned Kinglet, Dusky Flycatcher, Willow Flycatcher, Least Flycatcher.

Conservation Status:

Listed as Least Concern.

Capture Rates

A year round resident of British Columbia’s coastal areas, the Hutton’s Vireo prefers mixed evergreen forests as found on the perimeter of Colony Farm Regional Park. Therefore, Hutton’s Vireo are rarely seen at the banding station as reflected by the capture of few individuals in September and zero capture rate for the remainder of the year. Capture rates are standardized as birds captured per 100 net hours from 2010 – 2012.

Molt Summary:

PF: HY partial; PB: AHY complete; PA absent
Preformative molt includes 7 – 10 inner gr covs and occasionally s8, but no rects

Check also for P10 to be longer and more rounded (see Catharus thrushes) in HY/SY birds.

Molt limits occur among the greater coverts as in the photo below of a hatch year (HY) in September, the brownish tipped two retained outer greater coverts (GC1 & GC2) contrasting with the fresher, replaced inner greater coverts with more prominent whitish tips. Notice the narrow and tapered outer primary coverts with little or no greenish edging.

Notice also the retained inner greater covert (GC10), a key feather in partial preformative molts.

When songbirds replace less than all of their GCs in partial preformative molts, the innermost (GC 10) is often a skipped feather! (red arrow)