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Tucson Audubon Society
Dastardly Duos
Empidonax
Flycatchers: Hammond's, Dusky, & Gray
Tetxt by Larry Liese
Illustration by George C. West
(Article first appeared in the September 2004 Vermilion Flycatcher newsletter.
To receive the Vermilion Flycatcher in the mail, become a member of
the Friends of Tucson Audubon)
Now that I’ve got my i’s dotted and my t’s crossed, how best to end such an interesting journey? Empidonax Flycatchers of course! The classic hard-to-tell-apart genus of birds. If you’ve ever wondered what the word Empidonax refers to, it’s Greek for "King of the Gnats." I’ll let you ponder that one on your own.
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There are eleven empids shown in newer North American field guides, but we’ll be narrowing down the scope of our task to look at only three species regularly seen here in southeast Arizona. During fall migration Hammond’s (Empidonax hammondii), Dusky (Empidonax oberholseri), and Gray Flycatchers (Empidonax wrightii) can be encountered together giving birders a choice opportunity to practice their observing skills. A word of warning though folks—one should be content with identifying Empidonax flycatchers only as conditions allow. You must be content with ending your identification with "Well, it’s either a Hammond’s or a Dusky" if that’s all you can determine. Don’t feel you must end up with a singular species choice. It just might put some crow on your menu!
So, what does one look for to tell these birds apart? Colors won’t play as big a role here, though advanced birders can develop a feel for this and take advantage. Bill size, head shape, length of wings and tail, and habits will all play together in achieving identification towards a particular species. Making up your mind based on a single field mark can get you in trouble.
I think of these three birds as small, medium and large (H, D, G), though in actuality the differences are minor. Hammond’s is the smallest and lightest. It has a tiny bill that is almost all dark, and its relatively long primaries make the tail appear short in comparison to the others. It’s head sits on its shoulders in ‘Bulgarian weightlifter’ fashion, with not much of a neck showing. When perched it seems to like flicking its wings and tail together, which seems to fit with it having the longer primary extension.
Gray Flycatchers are larger and heavier than the other two. Their short primary projection and longer tail make them look stretched out and lanky in appearance. They have a long, thin bill that has a sharply defined dark tip. Unlike other Empidonax flycatchers, Grays pump their tails down instead of up, in a gentler manner. Although this is considered diagnostic, make sure other characteristics also agree before making an ID based on this.
When an empid isn’t a Hammond’s, and it isn’t a Gray, then I consider it a candidate for being a Dusky. I find this species to be hard to get a good handle on. The bill is intermediate between the others in length, with the outer half of the underside dark. It flicks its tail up like the Hammond’s, though perhaps not so much accompanied by wing fluttering. It has short primary projection making the tail appear long. To me, this is the classic empid, looking average in most aspects.
Is that enough to go on? Peruse the above titles for more, then try a field test. The whole month of September is good for finding them, and all are widespread in wooded and semi-open habitats in this fall migration period. Head out to the north end of Patagonia Lake where Sonoita Creek flows in and you could find all three!
Have fun with these toughest of duos, and farewell for now; it’s been a fun ride. Good luck!
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This page was updated on 02/21/06