35-B-2017 Least Flycatcher

STATUS
Accepted
DATE VOTING COMPLETED
1ST ROUND
7-0
HOW MANY OBSERVED?
3
DATE SIGHTING OCCURRED
DATE REPORT PREPARED
REPORTER
Austin Young
OTHER OBSERVERS
Austin Young
LOCALITY OF OBSERVATION
I observed the birds at the Mud Lake Wildlife Management Area Headquarters. It is located on the north side of the lake, at 43.9049, -112.3995.
HABITAT WHERE THE BIRD WAS OBSERVED
The habitat was cottonwood and willow riparian bordered by open sagebrush and agricultural land to the north, and bulrush marsh/open lake to the south. The patch of cottonwoods that the breeding pair was observed was approx. 50 meters long. The patch of cottonwoods where I heard the individual singing was slightly smaller and about 100 meters to the east.
SIGHTING DURATION, CONDITIONS, and EQUIPMENT USED
I observed the birds for 1 and 1/2 hours. It was warm and sunny with a slight breeze and 0% cloud cover. The birds foraged and sang within 20 meters the entire time, excluding one singing individual that was about 100 meters away in a separate cottonwood patch to the east. At one point, one of the Least Flycatchers foraged and sang within two feet of me, as I sat still observing it.
DID YOU TAKE NOTES?
Yes, during the observation
DID YOU CONSULT A FIELD GUIDE OR OTHER REFERENCE WORK?
No, not at all
WHICH GUIDE(S) OR REFERENCE(S): DID YOU CONSULT?
None
DESCRIPTION OF THE BIRD(s)
This is a classic-looking Empidonax flycatcher. However, it was distinctive with its combination of diagnostic song, short primaries, small bill, and the lower mandible of the bill was mostly orange.
BEHAVIOR OF THE BIRD(s)
During a significant length of time, I observed one breeding pair (one bird building a nest and the other continuously switching perches and singing in the same spot) and I heard one more individual Least Flycatcher singing in an adjacent patch of cottonwoods approx. 100 meters away.
It appeared that the same bird was building the nest while the other sang, proclaiming the territory to all. The one building the nest visited the nest 3-6 times every 10 minutes throughout the 50 minutes that I observed them.
The singing bird constantly sang from perch to perch between 0749 hours and 0855 hours. As time passed, it very gradually transitioned from non-stop singing to opportunistically catching insects to primarily foraging and less singing.
I also observed the singing Least Flycatcher actively being territorial and defensive towards a nearby Western Wood-Pewee.
Throughout the time that the singing individual sang, the other bird in the pair built the nest.
HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU?
The song clinched the identification. However, the combo of the smaller size, short primaries, mostly orange lower mandible, and the song all played a role in the identification.
HOW DID YOU ELIMINATE SIMILAR SPECIES? WHAT WERE THEY?
All Empidonax species are similar, of course. This habitat could have included Dusky Flycatcher, however that was quickly ruled out by song, short primaries, and mostly orange lower mandible.
WHAT IS YOUR EXPERIENCE WITH THIS (AND SIMILAR) SPECIES?
Extensive. I have observed many Least Flycatchers in the Billings, Montana area as well as a good number of them in Idaho. I understand their habitat preferences well as well as their song. I also have very extensive experience with Empidonax flycatchers in general.
DESCRIBE YOUR GENERAL BIRDING EXPERIENCE
Very extensive. I have been avidly birding, mostly in the Intermountain West, for about 10 years.
ADDITIONAL INFORMATION (If any)
It will take me a little bit to get a couple audio files to IBRC but the link to a video of the Least Flycatcher nest building is on my Flickr page here:
https://www.flickr.com/photos/145546172@N06/36622596751/
SUPPORTING IMAGES

FIRST ROUND VOTING:

Cliff Weisse
Accept

Description and photos support identification of Least Flycatcher.

s
Accept

The song is diagnostic and the added description was convincing

Carl Lundblad
Accept

Good description, good (and cool!) photos. I can't find any of the promised audio recordings associated with this record, unless I'm overlooking something, and the observer unfortunately never describes the song. However, I consider the photos diagnostic, the written details are good, and the observer experienced.

Jay Carlisle
Accept

good description & pics - & nice documentation of breeding!

Dave Trochlell
Accept

I'm convinced these were Least Flycatchers, but I wish the observer had described the song in the report.

Darren Clark
Accept

The report mentions the distinctive song (even though the song wasn't described in the report) of Least Flycatcher. The mention of the song, combined with images of the bird in a location where they have been regular for a few years support the identification of Least Flycatcher.

Doug Ward
Accept

While I am certain the identifications were good based on the description, habitat usage, and photos, was initially going to “reject” this record as the observer failed to describe the distinctive song of a Least Flycatcher (Empidonax minimus) in comparison to other similar species. However, after rummaging around in their public Flickr account (link provided), found a video with good audio to confirm.