Possible Black-chinned x Broad-tailed hummingbird
Photographed by Mark Chavez in Lakewood / Green Mtn area of Colorado
7 August 2007

all photos © 2007 Mark Chavez

Thank you, Mark, for your willingness to share this bird with others. 

Mark also commented:

• "The sound of the wings is not near as loud as a Broad-tailed and sounds more like a Black-chinned but seems to be much louder then other Black-chins.  It may be a case that I am more aware of this bird but I can always tell he is around because of the sound."

• "His upper gorget seems to have some green instead of black"

• "During the summer months we have Broad-tailed hummingbirds along with recent arrival Black-chinned the last five years.  Here along the front range in Colorado we have Rufous and Calliope also during migration.  I was guessing it was a hybrid Ruby-throated x Black-chinned.  This past summer I had several females that I assumed were Black-chinned but I had one that looked stubbier and did not pump her tail."

	FIGURE 1. Classic stretch pose.  Looks like I might see a tad bit of rufous edging along the top margin of R2.  Banks and Johnson (1961) reviewed a BCHU x BTLH which showed a very similar tail pattern and shape, down to the color of R1 and the upper tail coverts (and the virtual lack of any appreciable Rufous in the tail). Also I notice the sharp p10, along with the obvious gorget, the color of which is intermediate between Black-chinned & Broad-tailed (or Broad-tailed & Calliope, for that matter -- compare Fred Bassett's bird here. The tail gives no indication of Calliope, however, so I think we can rule the involvement of that species right off the bat.
	FIGURE 2. The gorget, again, is generally colored at the lower margin (as per Black-chinned), and the "tuxedo" effect of white below it is also suggestive of this species.
	FIGURE 3. Similar to Figure 2, but in flight...
	FIGURE 4. This "laid-out" pose is something I see regularly with Broad-taileds.  In fact, a superficial glance at this pic would suggest Broad-tailed to many birders.
	FIGURE 5.  The lower gorget border on this particular pic seems more ragged than some of the others.
	FIGURE 6.  Here we see the first of 3 spread tail / wing shots.  I'm struck with the pointedness of P10 here, as per Broad-tailed...
	FIGURE 7.  Another wing / tail shot.  I wish the wing tips were not obscured by the tail, as Archilochus parentage could be strongly indicated by notched tips...
	FIGURE 8.  The last of the series.  The shape of the retrices is pretty close to the drawing in Banks & Johnson (1961; p. 7) illustrating BCHU x BTLH.

What's the verdict, folks?.  After a review of the pics above and the write-up of a similar specimen in Banks & Johnson (1961), I suggest Black-chinned x Broad-tailed.  Agree?  Disagree?  Let me know why.

SJPeterson -at- aol.com

Sources:

Banks, R.C. and N.K. Johnson. 1961. A review of North American hybrid hummingbirds. Condor 63:3-28.