22 July 2017 – Ruby-throated Hummingbird

UPDATE!!

On 22 July, I published the following post with a methodical and detailed explanation of how I determined this window casualty to be an adult female Ruby-throated Hummingbird. On July 23rd, I received a kind message from Sheri Williamson who gently explained where I had erred in my interpretation.  Other than the fact that it was 1) a Ruby-throated Hummingbird and 2) dead, I had everything else wrong!  Sheri literally wrote the book on hummingbird identification, so I’m delighted to have her input and grateful for the chance to learn from her.

I have now updated this post with Sheri’s interpretation explained in this blue font. Read on, learn, and enjoy.  Thank you, Sheri!


 

In the midst of the hottest part of summer (105 F here today with a 111 heat index), I found this poor little hummingbird in the southeast alcove of the Noble Research Center.

Okay, but what hummingbird?  It’s too easy to just assume “Ruby-throated” and move on. There is no obvious rufous coloration on the back or at the base of the tail to suggest one of the Selasphorus hummingbirds, such as Rufous or Broad-tailed. The wingtips not quite reaching the tail tip does suggest Ruby-throated. (Wing chord 46.0 mm on this one.) The next most likely candidate – Black-chinned Hummingbird – has wing tips that reach beyond the tail tip. So I begin with the suggestion that it actually is a Rubythroat, but it’s time to really examine it now. (So far, so good.)

The first thing to do is figure out how old the bird is.  (Right here is where I mess up, and it’s all downhill from there.) Is it a hatch-year bird, i.e., one hatched this spring/summer?  If not, it’s an adult: “second-year” if I can determine that it hatched in 2016 or the more general “after hatch-year” if I can’t.  So, how do we determine age on a hummingbird?

The best way is to examine the bill for “corrugations.” Baby hummingbirds aren’t born with those long, pointy beaks.  They start out shorter and kind of pliable, slowly lengthening and stiffening during the first few months of life. (This bird’s bill is 16.5 mm in length.) You can see this, too – although it’s difficult with my aging eyes. If there are corrugations along something like 50–90% the length of the upper mandible (the “ramphotheca” for you Ornithology students out there), then you can be certain it’s an immature hummingbird you’re examining. Adults will show usually 0% or, sometimes up to about 10% of the bill’s length showing those corrugations.  What do you think about this bird?

All right, so this bird is an adult, i.e., AHY.

Nope!  It’s a hatch-year bird, and that changes everything.

My other clue should have been that there are thin, buffy edges to most of the contour feathers. This is a bird in fresh plumage. An adult female should show much more feather wear at this time of year.  Bill corrugations and buffy feather edges?  This little sprite started life in a nest in 2017!

All right, so this bird is an immature, i.e., HY. That means it can be pretty easily sexed.  (That part is still true, thankfully!) The most obvious feature for the North American Archilochus hummingbirds is the brilliant throat patch or gorget of males.  This bird doesn’t have one, although it does have 3 red feathers in the gorget area and heavy throat-spotting all over the gorget:

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That red looks ruby to me, too.

Okay, a few red feathers in the throat is not that rare among females.  (Actually, Sheri indicated that it is really rare.)  An adult male with so little red really would be odd.  (True, but the rest of this paragraph is wrong-o.) This bird looks like it might be an adult female, Ruby-throated Hummingbird. In fact, a second-year female hummingbird would be pretty unusual with that much spotting and red in the gorget.  That makes me suspect that this bird was not born in 2016 and we’ve already determined that it’s not from 2017.  That would mean that the bird is at least as old as a hatch-year from 2015.  In other words, hatch-year is ruled out by the bill and second-year is unlikely by the spotted gorget. Yes, this is an after hatch-year bird, but it’s more specifically an after second-year (ASY) in all likelihood.

Okay, we now know that it’s a hatch-year bird.  We also know that it’s got a heavily spotted gorget and already 3 ruby-reflecting feathers.  It’s a boy!  Yes, I mistook a young boy for a mature woman.

What else have we got?

Okay, the 6th primary feather on Ruby-throated Hummingbird has a weirdly-shaped tip.  In males, it looks like a tiny Samurai sword has sliced off the tip, leaving it with a slightly concave shape that sweeps up to a rather dramatic point on the leading edge.  (Although I don’t know for sure, I’m assuming that the shape of this one feather on the wing allows the males to make some kind of a mechanical sound for display.) On females – adult females – a shadow of that shape is present, too.  It’s a less dramatic sweep to a point, but the 6th primary definitely looks lopped off at its tip, just like this:

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According to the information in Peter Pyle’s identification guide, the feather shape on this bird is still a good match for an adult female . . . but it also is a good match for a young male. It’s still a boy.

The tail tips of female and immature Rubythroats of both sexes are just slightly notched or even straight across.  Especially on females, the outer tail feathers have broad, white tips. Adult males lack the white tips on their pointed outer tail feathers, and the tail shape ends up looking strongly notched or even slightly forked.  Here’s our bird’s tail:

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Checks out for female Ruby-throated Hummingbird. (But again, also checks out for an HY male.)

But wait – if this is an adult female Ruby-throated Hummingbird in latter July, then she should have at least attempted to breed over the past couple of months.  That means she should show a brood patch, just like this one:

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It kinda means that, but again Sheri was a font of great information. To wit, that’s not a brood patch! Evidently, hatch-year birds of both sexes have apteria (portions of skin from which no feathers are growing) on the breast and belly. Experienced hummingbird handlers know this.  Me? Not so much.

When I noticed what I thought was a brood patch on this bird, it colored everything else I thought about it.  “If it has a brood patch, it can’t be a hatch-year bird.” “If it has a brood patch, it can’t be a male.”  “If it has a brood patch, then those wrinkles I see on its bill can’t be the corrugations of a young bird’s bill.” My bias to weighting my opinion so heavily on something I was sure to be true definitely led me down the wrong path. I needed to apply better critical thinking than I did to avoid such a gaffe.

Which means . . .

There you have it: an adult female Ruby-throated Hummingbird. She had a nest and eggs at some point in recent weeks, though I can’t tell if she was successful with it.  She had left her territory and might have been engaged in some local dispersal to someplace favorable for molt. She might also have been in the midst of her fall migration and, given our hot weather for the past couple of weeks I wouldn’t blame her.  Either way, and whatever else might have transpired in her life as she alternated between winters in the Neotropics and summer in North America, she is another senseless loss to a window pane in our inhospitable human landscape.

None of that is true. Instead . . .

There you have it: a young male Ruby-throated Hummingbird. He was recently out of the nest and was likely on his first foray from his natal territory. Had all gone well for him, he might have ended up in southern Mexico or Guatemala or Panama. Had he survived the winter, he would’ve packed on as much fat as possible and zoomed out over the Gulf of Mexico some evening in the hope of making it back to the US after 18 hours or so on the wing.  Then he would have kept going, orienting to an area probably not too far from where he was born, and prepared for a few months of pitched battles against his rivals and aggressive wooing of the ladies.

He didn’t get the chance, however. Like nearly a billion of his feathered comrades in the US each year, he fell victim to a stupid pane of glass while passing through a human-dominated landscape that can be fraught with danger for wild birds. RIP, young lad.

30 June 2017 – three casualties

I was out of town from 21–30 June and no surveys were run during that time.  On June 30th, however, I heard from Dawn Brown and Corey Riding that there were three casualties at the southwestern alcove of the Noble Research Center: a badly decayed Northern Parula (adult male), a female Ruby-throated Hummingbird, and a female (with brood patch!) Indigo Bunting.  It’s possible that the bunting came in on the 30th, but the others were clearly killed prior to that date. (Photos by Dawn Brown.) This is officially the first Northern Parula found on the project.

5 September 2016 – Ruby-throated Hummingbird

The HY male Ruby-throated Hummingbird I found this morning means that, for 2016, a young male of this species was both the last casualty of “spring” (on July 11th) and the first official casualty of fall.

This bird was in the southwest alcove, illustrating the urgency with which I must complete my ABC bird tape treatments of the west entrances!

11 July 2016 – Ruby-throated Hummingbird

I found a presumptive HY male Ruby-throated Hummingbird in the southwest alcove of the NRC today.  I left it in place for a removal trial.

I did not obtain photos of the bill showing corrugations.  Instead check out the single ruby gorget feather and concave tip to primary feather #6 as indications of a male.  The bird carried no fat.

18 August 2014 – Ruby-throated Hummingbird (another one)

Another day, another window-killed hummingbird.  This one was heading north when it met its end. This is the 10th hummingbird fatality, and the 180th overall.

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Regular readers will note a very similar post from yesterday, and a superficially very similar-looking bird. 

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This one was more obviously a Ruby-throated Hummingbird.  The following photo illustrates that the tailtip extends well beyond the wingtips.

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Next, I examined the bill to look for corrugations indicative of a hatch-year bird.  I can’t see any.  This looks like an after hatch-year bird; plumage-wise, she’s female.

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So I’ve got an AHY, female, Ruby-throated Hummingbird.  I checked one last thing to clinch that identification – the shape of the 6th primary.  Sure enough, it’s a perfect match for the shape indicated as “AHY/ASY” female Ruby-throated Hummingbird in Peter Pyle’s Identification Guide to North American Birds.

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17 August 2014 – Ruby-throated Hummingbird (I think)

Today marked the inauspicious observance of the first window-killed bird at the Noble Research Center for fall, 2014.  It was a hatch year Archilochus hummingbird at the southwest alcove that I have somewhat tentatively identified as a Ruby-throated. To nail down the identification as best as I could, I consulted David Sibley’s the Sibley Guide to Birds (2000) and Peter Pyle’s Identification Guide to North American Birds (1997).

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Step 1 for identification of these hummingbirds is to confirm the age.  As hatch-year hummers develop, their bills lose characteristic striations or corrugations over time. A hummingbird with these markings extending for > 10% the length of the bill can be reliably considered HY/SY (i.e., less than 1 year old).   Here’s this morning’s bird (with bonus photo of hummingbird tongue tip):

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The markings are evident over probably 90% of the bill length. This is a hatch-year bird.

The problem with the bird is that it presents some characters (admittedly subjective in some cases) that suggest Black-chinned more strongly than Ruby-throated.  For example, there is low contrast between the auriculars and the throat, and that throat is spotted.  Both of these are Black-chinned characters as rendered by Sibley. The flanks are dirty gray with just a hint of cinnamon – also suggesting Black-chinned.  More pronounced is the relative length of folded wing and tail:  If anything, the wingtips extend beyond the tail tip as opposed to obviously shorter than the tail as typical for Ruby-throated. 

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So it was going to take some measurements to help solve this puzzle.  The wing chord came in at 46.5mm:  that’s too big for a male of either species.  So with that information, I knew I now had a HY, female hummingbird.

The length of the tail (24.9), culmen (18.8), and tail fork (0.10) – and the width of the outermost tail feather (r5, 5.2) offered no help in determining which HY female Archilochus I had.  However, the shape of the outer primary (p10) and primary #6 (p6) were both in line with expectations for Ruby-throated.  The photos aren’t great, but p6 is featured in the next two photos:

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So, based on my analysis of the characters this bird presented, I’m calling her a Ruby-throated Hummingbird.  The possibility of hybrids is very real for this species and Black-chinned, however, so I will be sharing this information with some more experienced folks to get some other opinions.  Stay tuned!

31 August 2012 – Ruby-throated Hummingbird

An immature male Rubythroat met an untimely end at the southwest alcove of the NRC today.  The ants were upon him, so I left him in place to see how long he lasts.