Description:

Western Wood-Pewees are small nondescript birds (members of the Tyrannidae) that are common across western North America. Despite the widespread abundance of Western Wood-pewees, we know very little 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.

Identification:

General: Western Wood-Pewees are fairly small birds, with relatively large heads and “whiskers” surrounding their broad, flat bills. Adults measure about 16 cm long and weigh 13 grams.

Adult Male: and Female: Males and Females tend to be very similar in appearance with the exception the females are slightly smaller. Upperparts mainly greyish/olive coloured, white or pale wing-bars and tertial edges, underparts are a subdued white. Dark upper mandibles, pale lower mandibles. Absence of eye ring.

Juvenile: For the most part juveniles resemble adults, with the exception that juveniles usually appear darker and tend to have buffy wing-bars.

Similar Species: Very difficult to distinguish from Eastern Wood-Pewee by sight alone. Range maps and song help to distinguish these two species. Greater Pewees are larger, with bright pink/orange underparts and sport a slender pointed crest. Olive-sided Flycatchers have easily distinguishable from Western Wood-Pewees by their song, but they are also larger and have a more prominent white chest due to darker patches that surround the breast. Western Wood-Pewees are distinguished from Empidonax flycatchers by their larger size, darker head, dusky breast and longer wings.

Behaviour: These birds are almost never seen hopping or walking on the ground, instead they are either perched or flying through the air. These birds are solitary.

Habitat: Common in open woodlands including mature deciduous and mixed forests, along forest edges and riparian habitats.
Information: Western Wood-Pewees usually perch high up on the tops and canopy of trees and dash out to catch insects. Prey items include flying insects including flies, ants, bees, wasps, beetles moths and bugs. They may hover in the air while flying and foraging for food and may quiver their wings once they have returned to their perch.
Few data exist on longevity; however, the oldest recorded individual was at least 6 years old.
Based on the limited amount of information that is available, it appears that Western Wood-Pewees typically lay between 1 and 5 eggs, clutches of 3 eggs being most common. Depending on breeding habitat, nest survival ranges from 43 to more than 60%. Predation is the main cause of nest failure.

Conservation Status: (Least Concern)

Populations appear have benefited from forest fragmentation and the creation of edge habitats. Despite being relatively common across their range, according to the Breeding Bird Surveys they are declining in Canada and United States. Declines are attributed to expansion of urban centres and land conversion for agricultural purposes that have resulted in a loss of suitable habitat. Of particular concern is the removal of tropical forest in their wintering habitat.
 

Capture Rates