19 August 2017 – Painted Bunting

I actually discovered it on my 8/20 survey, but this poor little bird on the 20th was already seething with maggots so I’m comfortable calling it an 8/19 casualty. This was a second year male.  Check out the feather wear on his primaries.  He was headed south to molt and then continue on further south.

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10 August 2017 – no casualties

Both hummingbird carcasses still in evidence. The whole bird from the southeastern alcove has been decapitated, presumably by the ants.

The tail from the southwestern alcove made things a bit more interesting by being gone.  I wasn’t too surprised by that because we had storms roll through overnight that I assumed would have blown that little bit of feathers away.  So I started looking around just to see if I could figure out in which crack in the bricks it ended up.  I couldn’t find it, but my more intensive searching did turn up these tidbits:

Screen Shot 2017-08-10 at 8.51.25 AM  Screen Shot 2017-08-10 at 8.51.50 AM

Aha!  So it looks like yesterday’s tail was not necessarily from a hummingbird that had been scavenged.  It looks more like a lawnmower got it. It also seems to have been a HY male, Ruby-throated Hummingbird.

9 August 2017 – 1.33 hummingbirds

Hummingbirds have been takin’ it in the shorts of late . . .

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But what’s with the fractional hummingbird reference above?  Well, “scavenging” and “removal” are not necessarily the same thing. Often I find the remains of a bird that has been scavenged, but there’s enough left behind that I am able to detect that a casualty has occurred. Those remnants – let’s say a pile of flight feathers left behind by a scavenging cat – can last in place for many weeks.  Each time I survey for casualties I’m greeted at that spot with the information that a bird died there (or at least somewhere nearby) even though all the edible bits are long gone. We should be clear that scavenging isn’t the important rate to help us better estimate detection of window-killed birds, removal is.  It’s only when every piece of that carcass is gone that I’m unable to detect the evidence of a casualty.

We see this played out all the time with hummingbirds.  For some reason, the ants seem to get to the hummingbirds more quickly than they get to other birds.  (I have some hypotheses about this, e.g., that hummingbirds are more often flying in daylight and might have lain in place longer than the night-flying warbler and sparrow migrants.) The result is that hummingbird carcasses are rarely in pristine shape when I find them, but they are still there.

Check out hummingbird #1 this morning from the southeast alcove.  First, look how obvious it is to detect the carcass even from ~20m away.  Up close, note that a good bit of her face has already been carted away, one ant-mandible-sized piece at a time.

 

 

This next one (or 0.33 of one) from the southwest alcove will put your observational skills to the test:

See it yet?

 

 

Oh, that explains it!

 

 

In this case, there’s a pre-scavenged hummingbird (likely also AHY-F Ruby-throated) that is represented by its tail only. But it’s still detectable and largely identifiable.

(UPDATE 10 AUGUST 2017: Today I found a head and wing near where I found the tail on Aug. 9. First, this looks much more likely as a HY-M than an AHY-F.  Also, literal scavenging seems less likely.  I suspect more that the carcass was chopped up by a lawnmower.)

Spring/Summer 2017 was busy

As I’m about to head out for a conference this week, spring and summer monitoring comes to a close.  I’ll begin August 2017 the 9th consecutive year of (mostly) daily monitoring for window casualties at the Noble Research Center on the campus of Oklahoma State University in Stillwater, Oklahoma, USA.

It’s been a busy spring.

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Beginning Mar 1st, here’s what has turned up at the Noble Research Center.

Dead Birds

  1. Indigo Bunting – 5
  2. Painted Bunting – 5
  3. Ruby-throated Hummingbird – 3
  4. Lincoln’s Sparrow – 2
  5. Mourning Dove – 2
  6. Nashville Warbler – 2
  7. Orange-crowned Warbler – 2
  8. Baltimore Oriole – 1
  9. Chipping Sparrow – 1
  10. Eastern Meadowlark – 1
  11. House Wren – 1
  12. Northern Parula – 1
  13. Tennessee Warbler – 1
  14. Yellow-billed Cuckoo – 1

That’s 28 individuals of 14 species, and damn, that is disheartening.

On the plus side, my commitment to checking almost every day has put me in position to save a few birds by getting them safely away from the building and taking them someplace secure to rest and recuperate for a bit. I can’t guarantee that all 6 of these survived the ordeal, but they seemed to be in good shape when I last saw them:

  1. Northern Cardinal
  2. Common Yellowthroat
  3. Mourning Dove
  4. Song Sparrow
  5. Yellow Warbler
  6. Carolina Wren

 

 

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:

Screen Shot 2017-07-22 at 6.27.47 PM

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:

Screen Shot 2017-07-22 at 5.57.50 PM

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:

Screen Shot 2017-07-22 at 5.57.30 PM

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:

Screen Shot 2017-07-22 at 6.26.29 PM

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.

10 July 2017 – Eastern Meadowlark

Monday dawned bright but soon turned sombre when I encountered the study’s first meadowlark (61st species; presumably Eastern) at the northeastern alcove. Worse, it was a baby: HY-U.  Worse still: it was alive but mortally wounded and suffering greatly.  It was having spasms, was unable to hold its head up, panting heavily, and bleeding through its bill, which was bent at the tip from the collision.

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This is the reality of the catastrophic but not immediately fatal injuries that millions of birds endure every year. For those of us who dedicate our time to count them, we must be prepared to come face-to-face with some of our favorite creatures sometimes in the throes of a horrible and painful death.  Sometimes we are even faced with the decision to intervene and usher in a more swift and merciful death than the one being endured. So that’s how my Monday morning began: euthanasia via thoracic compression of a baby meadowlark enduring unimaginable pain and fear.

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The meadowlark did not recover from its window collision today, and I’m not sure I will either.

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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.