Western Flycatcher

Empidonax difficilis

*Range Map of the Pacific-Slope complex — Second map shows the range of the “Cordilleran” complex*

The Pacific-Slope Flycatcher is a member of the “Western Flycatcher” complex. It was split, along with the Cordilleran Flycatcher, in 1989. Not all scientists agreed on this split. Scientists such as Douglas Futuyma have reviewed the genetic studies. Andrew Rush, who authored genetic research papers, disagreed with the 1989 AOU decision to split the Western Flycatcher complex. Citing the following quote from the authors: “We now wonder whether, given the present evidence, the decision to formally split would have been made.” Douglas Futuyma further stated, “If it were up to me to hand down AOU decisions, these forms would be retired, and we would go back to a single species, Western Flycatcher. I hope the AOU ultimately comes around to that view.”

In 2023, the AOU finally accepted arguments such as those expressed above. Taxonomists conclusively put to bed the controversy.

There are six recognized subspecies of Pacific-Slope Flycatcher:

E. d. difficilis breeds in the Pacific states and Canadian provinces from southeastern Alaska, south to northern Baja California, Mexico.
E. d. insulicola breeds on the Channel Islands off southern California.
E. d. cineritius lives in the mountains of southern Baja California (Mexico).
E. d. hellmayri Breeds inland from west Texas (e.g., Brewster County) and
northwestern Mexico
E. d. bateli, Breeds in mountains of Mexico west of the Isthmus of Tehuantepec, excluding the Sierra Madre del Sur, north to Sinaloa, Chihuahua, and Coahuila.
E. d. occidentalis, the Sierra Madre del Sur of Guerrero and southern Oaxaca, Mexico

I would not be surprised to see further refinement in describing the various subspecies assignments. Why the scientific name for the species (difficilis) was not replaced with the Latin occidentalis, (meaning Western) is a mystery to me.

I enjoy meetings with these birds each spring in my southern California home. I usually hear them before I see them. I recall my excitement when I first photographed one of these birds in mid-March 2002, hawking tiny insects in my patio. I’d never seen a bird so alert and focused on snagging insects from the mid-air.

Range Map for Western Flycatcher — *Range Map*

27 Photos

Pacific-Slope Flycatcher - Empidonax difficilis — **Pacific-Slope Flycatcher**
*(Empidonax difficilis)*

**Description:**
San Felipe Creek near Scissors Crossing in the Anza-Borrego desert of San Diego County CAlifornia USA 2009-04-10.
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**Date Taken:** 2009:04:10 12:21

**Location:**

Scissors Crossing
Anza-Borrego, California
United States
2293.42 ft above sea level

**Camera Information:**
NIKON D2X, 800 mm, f/5.6, 1/800

**File Name:** JCD5325.PacificSlopeFlyCatcher

© 2009 Jack Daynes, shadeTreeImaging.com

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Pin It — **Pacific-Slope Flycatcher**
*(Empidonax difficilis)*

**Description:**
San Felipe Creek near Scissors Crossing in the Anza-Borrego desert of San Diego County CAlifornia USA 2009-04-10.
Read More

**Date Taken:** 2009:04:10 12:21

**Location:**

Scissors Crossing
Anza-Borrego, California
United States
2293.42 ft above sea level

**Camera Information:**
NIKON D2X, 800 mm, f/5.6, 1/800

**File Name:** JCD5325.PacificSlopeFlyCatcher

© 2009 Jack Daynes, shadeTreeImaging.com

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