The Willow Flycatcher (Empidonax
traillii) is associated with willow bushes and other deciduous shrubs in open
habitats across North America.
documentation regarding distribution and abundance of the Willow Flycatcher population in Alberta is due, in part, to the confusion of the split between the Alder and the Willow Flycatchers. Consequently, the
status of the Willow Flycatcher was listed as Undetermined in the 1985, 1991 and 1996
Provincial Wildlife Status reviews. This report summarizes recent and historical information on the Willow Flycatcher in Alberta and elsewhere in order to facilitate the update of the status of the
species in the province.
The Willow Flycatcher breeds in a variety of shrubby habitats across North America. Its habitat preferences are well documented for eastern North America, the southwestern United States and the Pacific Northwest. Typically, upland sites supporting a mixture of shrubs including willow, hawthorn and rose are preferred. In Alberta, the Willow Flycatcher has historically occupied relatively dry, upland,
shrub dominated sites. During surveys in Alberta in 1999, Willow Flycatchers were found in shrubby wetlands, road and rail ditches, and brush around lake margins. The species also occurred in the mesic habitats typical of Alder Flycatchers. The surveys provided no evidence that dry, upland habitats currently support any Willow Flycatchers.
Habitat patches were in low-lying areas where water tends to collect such as valley bottoms, lake edges, or ditches along roads.
As their name
suggest, willow bushes are an integral part of the Willow Flycatcher's habitat. The average height of the willows in Willow Flycatcher territories is about 2 metres and the bushes are often densely packed. Water or grassy areas are often interspersed among the willow patches. Most Willow Flycatcher territories contain open water and the remaining sites have water nearby; standing water
is typical although some sites may also contain moving water. A common feature of most Willow Flycatcher territories in Alberta is the presence of spruce trees or snags that rise above the canopy amid the willow patch. These trees are used for perching and as launching points for display and foraging flights.
The Willow Flycatcher is a small flycatcher (140 millimetres long, and
weighing approximately 11 grams) in the family Tyrannidae, with a medium-dark, brownish olive to grayish olive back and head, two light wing-bars and light underparts with a brownish olive breast band and slight yellow wash to the vent. The Willow Flycatcher is insectivorous and catches insects on the wing.
The only reliable method of identifying Willow Flycatchers in the field is by their songs. This is especially critical when trying to distinguish the visually identical Willow and Alder Flycatchers. Both male and female Willow Flycatchers sing. The standard advertising song of the Willow Flycatcher is
"afitz-bew". It will also emit a sharp, dry "whit" as well as
a "zbew". Many sources have noted that the Willow Flycatcher begins to vocalize much earlier in the day than other bird species within the same habitat. In Alberta, vocal displays are often performed from tall spruce trees that offer an unobscured view of the bird's territory. Where spruce is not present, bare willow branches are often used and in some sites Willow Flycatchers use overhead powerlines as perches. These display perches are also used to initiate foraging sallies.
The Willow Flycatcher arrives on its breeding grounds in Alberta in late May. Males arrive up to two weeks earlier than females to set up territories.
Willow Flycatchers build their nests in shrubs at the forks of branches. If shrubs other than willow occur in the nesting habitat, they are selected as alternate nest sites.
Three to four eggs are laid and incubated for approximately 16 days. Both parents take part in feeding the nestlings.
The Willow Flycatcher typically leaves Alberta for its wintering grounds in August.
Reprinted from Alberta Wildlife Status Report No. 29
with permission from Alberta
Sustainable Resource Development.