Western Wood-Pewee

The Western Wood-Pewee is a medium size and inconspicuous flycatcher, common across western North America and, almost identical to its eastern counterpart, the Eastern Wood-Pewee. Despite the widespread abundance of Western Wood-pewees, very little is known about their biology during migration and wintering months. The breeding distribution of this species is remarkable, spanning from central Alaska through California, Mexico and possibly reaching north central Costa Rica. The western limit of the range follows the coast while the eastern range spans from Alaska to the Yukon, central Saskatchewan, central Manitoba, central South Dakota, western Nebraska, eastern Colorado, eastern New Mexico and western Texas. Due to the striking similarities between Western Wood-Pewees and Eastern Wood-Pewees and the potential for the misclassification of migrating birds as wintering birds, delineating the wintering ranges of these two species becomes a challenge. To the best of our knowledge, Western Wood-Pewees spend their winter months in parts of Central America and northern and western South America.

Adult Male (spring/summer)

Head is dull olive-gray; cap is darker with slight crest and week partial eye-ring. Pale gray throat; dusky ‘vest’; pale gray belly and grayish smudges on undertail coverts. Back, rump and uppertail coverts dull olive-gray. Wings and tail are dark olive-gray with white feather edging. Two narrow grayish wingbars. They have long wings and long primary projections as well as relatively short legs.

Adult Female (spring/summer)

Similar to adult male.

Juvenile

Similar to adult but slightly darker and dull, not very contrasting buffy-grayish wingbars; upper weaker than lower.

General:

Medium sized flycatcher. Length: 14-16cm. Wing: 26cm. Weight: 11-14gr.

Behaviour:

Sallying or flying out from a branch in the middle part of understory to catch flying insects, it is a sit and wait predator. Its diet consists of insects almost totally caught in flight. It can be difficult to locate while perched and may be located initially by its song.

Habitat:

Common in open woodlands including mature deciduous and mixed forests, along forest edges and riparian habitats.

Information:

The nest is a shallow cup of woven grasses bound together with spider webs and covered with moss and other vegetation placed in a fork of a horizontal branch. Clutch is 1-5 creamy white eggs wreathed with brown blotches and spots at the widest point. Both parents feed the young. This wood-pewee is generally an infrequent host to cowbirds.

Similar species:

Eastern Wood-Pewee, Olive-sided Flycatcher, Greater Pewee, Dusky Flycatcher, Least Flycatcher.

Conservation Status:

Listed as Least Concern but experiencing a slow steady decline in numbers most likely due to habitat loss in breeding and wintering grounds.

Capture Rates:

A breeding bird in Colony Farm, capture rates of the Western Wood-pewee occur from early spring through August. Numbers peak in June as they settle into territories then again in August as juveniles disperse and individuals prepare for long distance migration to their wintering grounds in South America.

Molt Summary:

PF: HY/SY incomplete (Oct-Apr); PB: AHY/ASY complete (Aug-Mar); PA absent.
Preformative molt includes all feathers except pp covs.

From Empidonax flycatchers by much longer wing. Like ‘Traill’s’ Flycatcher P6 is not emarginated and there is no eyering but the dark vest is very different from any Empid as are the smudged undertail coverts. This flycatcher has a very long primary projection and the bill is much longer, the underside being 1/2 to 3/4 dark (photo below left) versus pale on Willow Flycatcher (photo below right).

The wing tips reach to the tips of the undertail coverts, on Traill’s Flycatcher they are much shorter.

Like most Tyrant flycatchers WEWP molt primarily on their winter grounds so separating adults from hatch year birds is relatively easy.
Freshly molted wing bars of HY flycatchers are buffy/cinnamon in appearance and fresh looking having just grown in this summer. An adult bird now carrying 6-8 month old feathers that have been used for one long distance migration, and which have been worn for an entire breeding season appear worn and whitish, not buffy like this bird.

The buffy fringes to the median and greater coverts form the upper and lower buff wing bars diagnostic of juvenal birds.

This AHY in June is showing lesser coverts which are uniform in colour and median and greater coverts which are tipped with pale grayish. The outer primary coverts are broad and truncate. Notice this bird abnormally had 4 alula feathers.

The tail of the same bird shows the very broad, truncate appearance of adult retrices with a distinct corner to the inner web of r4 (indicated by the red arrow).