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Montana Field Guide

Montana Field Guides

Alder Flycatcher - Empidonax alnorum

Species of Concern
Native Species

Global Rank: G5
State Rank: S3B

Agency Status

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Copyright by Borror Laboratory of Bioacoustics, Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, all rights reserved.
General Description
Although large in the Empidonax genus, the Alder Flycatcher is a small species within the flycatcher family. Thirteen to seventeen centimeters in length, with a wingspan of approximately 21 cm, the Alder Flycatcher has dull greenish-olive upperparts with a similarly colored, but darker, crown. The eye-ring is narrow, whitish, and sometimes indistinct but rarely lacking, while the throat is clearly white and contrasts with a gray breast band. The bill is black on the upper mandible and dull yellow-orange or pinkish on the lower. The wings are darker than the back, have white-edged tertials (innermost secondaries) and wing-bars that are whitish and boldly marked (Lowther 1999).

The vocalization of the Alder Flycatcher is a harsh and burry, three syllable "rreeBEEa" or "fee-BEE-o" (Lowther 1999, Sibley 2000). For a more complete description, see below on distinguishing between the vocalizations of the Alder and Willow (E. trailii) flycatchers.

For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.

Diagnostic Characteristics
Other flycatchers found in Montana with which the Alder may be confused are the Least (E. minimus) and Willow Flycatchers. In comparison, the Least Flycatcher has a shorter, narrower bill, a bold, complete eye-ring, thinner tail, and different song (Lowther 1999, Sibley 2000). The general appearance of the Alder Flycatcher is so similar to that of the Willow Flycatcher that separating these two species visually can be extremely difficult (Lowther 1999).

The Alder Flycatcher is best separated from the Willow Flycatcher by voice. The song of the Alder Flycatcher (a 3-syllable "fee-BEE-o") is described as being harsh and burry in nature with a strongly accented second syllable, making it sound like a 2 syllable "rrree- BEEP" (Lowther 1999). The song of the Willow Flycatcher is accented on the first syllable, more of a "FITZ-bew," but may occasionally sound as though it has a subtle third syllable, "FRITZ-be-yew" (Lowther 1999). The call of the Alder is described more as an emphatic "pip" or "pit" (reminiscent of an Olive-sided Flycatcher) in contrast to the liquid "whit" of the Willow (Gorski 1969a, 1971, Lowther 1999, Sibley 2000). Lowther (1999) indicates that, generally, the Alder has a darker overall appearance, "slightly greener crown, more pointed wings, slightly shorter bill, and slightly longer tail."

Species Range
Montana Range Range Descriptions

All Ranges
(Click legend blocks to view individual ranges)

Western Hemisphere Range


Observations in Montana Natural Heritage Program Database
Number of Observations: 337

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density


SUMMER (Feb 16 - Dec 14)
Direct Evidence of Breeding

Indirect Evidence of Breeding

No Evidence of Breeding

WINTER (Dec 15 - Feb 15)
Regularly Observed

Not Regularly Observed


(Observations spanning multiple months or years are excluded from time charts)

Observations in May indicate the earliest presence of the species in the state. Alder Flycatcher records continue generally only through July, with one rarity; an individual at Pine Butte that was observed in September of 1991 (Montana Bird Distribution Committee 2012).

Habitat use is similar to that of the Willow Flycatcher and includes willow (Salix) thickets, red osier dogwood (Cornus sericea), or birch (Betula sp.) along the edges of wetlands, streams, lakes, and forests (Johnsgard 1992).

Ecological Systems Associated with this Species
  • Details on Creation and Suggested Uses and Limitations
    How Associations Were Made
    We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
    1. Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
    2. Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
    4. Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
    Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.  In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.  However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if point observations were associated with that system.  Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.  The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.  If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.

    Suggested Uses and Limitations
    Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.  These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.  Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.  Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.  Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).  Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.

    Literature Cited
    • Adams, R.A.  2003.  Bats of the Rocky Mountain West; natural history, ecology, and conservation.  Boulder, CO: University Press of Colorado.  289 p.
    • Dobkin, D. S.  1992.  Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34.  Missoula, MT.
    • Foresman, K.R.  2012.  Mammals of Montana.  Second edition.  Mountain Press Publishing, Missoula, Montana.  429 pp.
    • Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998.  Montana atlas of terrestrial vertebrates.  Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT.  1302 p.
    • Hutto, R.L. and J.S. Young.  1999.  Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32.  72 p.
    • Maxell, B.A.  2000.  Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species.  Report to U.S. Forest Service Region 1.  Missoula, MT: Wildlife Biology Program, University of Montana.  161 p.
    • Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath.  2004.  Amphibians and reptiles of Montana.  Missoula, MT: Mountain Press Publishing Company. 262 p.

Food Habits
The Alder Flycatcher's diet is comprised mainly of insects obtained primarily by flycatching (Bent 1942), although gleaning prey from tree and shrub foliage is also a known foraging behavior (Lowther 1999). Berries supplement their winter diet (Stiles and Skutch 2003).

In areas where breeding ranges overlap, Alder Flycatchers show less aggression toward Willow Flycatchers near nesting sites than any other species; Willow Flycatcher are the more dominant of the two species (Gorski 1969b).

Reproductive Characteristics
No direct evidence to support breeding in the state has been documented, although the species is suspected of breeding at Pine Butte Preserve, Teton County (Montana Bird Distribution Committee 2012). Other locations where the species has exhibited behavior to suggest breeding include Smith Lake (Flathead County), Cougar Creek (Gallatin County), and Fisher River (Lincoln County).

In areas where this species breeds, the nest is described as somewhat bulky and loosely constructed of soft dead grasses, leaves and other plant fibers, moss, and bark, sometimes with feathers, and lined with finer grasses, plant fibers, and hair (Baicich and Harrison 2005, Lowther 1999). It may also have an untidy appearance, with hanging tails or streamers (Baicich and Harrison 2005). Nests are located in damp thickets of alder and various shrubs, in bogs, along marshy borders of lakes, and in brush along stream banks, and are usually placed less than 2 meters above ground (Harrison 1979). The average clutch size of subelliptical to short-elliptical eggs is 3 to 4, sometimes 2. The eggs are 18x13 mm in size and are smooth, non-glossy, white or creamy-white, possibly tinted buff or pink, and unmarked or lightly marked with light red, or reddish-brown, primarily on the larger end (Baicich and Harrison 2005). Incubation, by the female, lasts 13 to 15 days, and the young, tended by both parents, fledge at 12 to 15 days.

No information is available on management activities in Montana specific to Alder Flycatcher, although the suspected breeding location for this species is protected within Pine Butte Preserve.

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Alder Flycatcher — Empidonax alnorum.  Montana Field Guide.  .  Retrieved on , from