Least Flycatcher

One of the most difficult Empidonax species to visually identify, the Least Flycatcher can otherwise be easily identified by its persistent “chebec” song. It breeds from southern Yukon, southern NWT, south and eastward through the Canadian provinces and the northern United States to southern Newfoundland and central Labrador, the northeastern United States and along the Appalachians south to northwest Georgia. This flycatcher winters in southern Florida, Mexico, Honduras and northern Nicaragua.

Adult Male (spring/summer)

Adult Male (spring/summer)
Upperparts, wings, and tail brownish-olive to slate gray, greater and median wing coverts tipped ashy-white to lemon-white forming two wing bars. The underparts are whitish, washed with dusky-grayish on breast and flanks and slight yellowish on belly. The lower mandible generally has a dusky tip with a yellow-orange base. The throat is white with no yellowish cast. The ashy-white to white eye ring is complete or nearly complete. The legs are blackish.

Adult Female (spring/summer)

Sexes are similar.

Juvenile

Eye ring less distinct on some individuals, but always present. Dull slate gray above with buffy wing bars.

General:

Small flycatcher. The sexes are similar in plumage. Length: 12.5-14cm. Wing: 19-20cm. Weight: 10.3grams.

Behaviour:

As like other flycatchers, the Least perches on branches of trees to fly out and catch insects, frequently returning to the same perch. Most insects are caught in mid-air but it will forage while hovering near foliage for spiders and caterpillars.

Habitat:

Generally seen in open woods, aspen groves, orchards, and shade trees. Breeds in deciduous or mixed woodlands, seldom in purely coniferous groves and usually around clearings or edges. However, it is sometimes known to breed in the interior of dry woods.

Information:

Least Flycatchers are known for their propensity to form overt clusters of territories during the breeding season. In the spring, males sing incessantly and establish small territories in highly dense clusters that resemble classical leks. Extra-territorial forays by males and females often result in aggressive chases and fights during peak female fertility.

Females weave their nest from fine grasses, placing it in the crotch of a small tree or shrub, or saddling it on a limb or large branch. Three to six creamy white eggs are laid.

Similar species:

Willow Flycatcher, Alder Flycatcher, Eastern Wood-Pewee, Acadian Flycatcher.

Conservation Status:

IUCN conservation status listed as Least Concern.

Capture Rates

Although appropriate habitat at Colony Farm, the Least Flycatcher’s range doesn’t usually extend as far west and therefore an exciting occurrence in the park, reflected by the capture of two individuals, believed to be a pair, caught in June and July of 2012. 

Molt Summary:

PF: HY partial (Jul-Oct), AHY complete (Jul-Nov); PA SY partial-incomplete (Jan-May), ASY partial (Feb-Apr).
Preformative molt occurs primarily on the summer grounds and includes few if any wing covs and no flight feathers. Some molting can extend into migration or occur on the winter grounds.
Adult PB: can commence on the summer grounds, but most replacement occurs on the winter grounds.
1st PA: usually includes most or all med covs, 3-9 gr covs, usually 1-3 terts, occasionally s6, and 0-12 rects. is protracted with replacement of some flight feathers (usually s5-s6 and p7-p10) often being suspended over the winter; can be extended into migration.
Adult PA: includes 2 – 10 inner gr covs, 1 – 3 terts, and sometimes 1-2 central rects.

Molt limits occur among the greater coverts and tertials. This SY bird in June has replaced inner greater coverts and retained a single outer greater covert (GC1) and all 3 tertials, the molt limits shown with the red arrows. Notice the brown and abraded outer GC contrasting with the fresher and whitish tipped replaced inner GCs and the more prominently edged replaced tertials (S7-S9) contrasting with the adjacent secondaries.

Notice also the narrow, tapered and more lightly pigmented retained outer primary coverts and lower main alula feather (A3).

The tail of the above SY bird in June is showing mixed tapered and truncate rectrices typical of first year birds which can replace all rectrices during the first PA molt.

The tail of this SY bird in June is also showing mixed tapered and truncate rectrices having replaced the 3 outer rectrices (R4-R6) and R1 and retained rectrices R2 & R3. Notice the relatively worn, brownish and tapered retained feathers (red arrows).