What's That Bird? Using Science to Decide

Facebook groups. To me, they're like folk festivals: best when they're small. And then they get too big, really fast, and you suddenly realize you can no longer abide them. At least that's how it has always worked for me. There's this sort of tipping point where the people who have no idea what they're talking about (but are loud) outnumber the ones who do (who are quiet) and that's when I vamoose.

I think being in isolation for too long has made me peek in on Facebook groups lately. The ones having to do with natural history ID can frustrate me terribly, because you'll no sooner get somebody's critter identified than you'll be drowned out by ten people, all guessing away but sure they're right, some of them openly and none too politely shouting you down.  That's no milk snake! That's a TIMBER RATTLER!! And I'd wind up wondering why I'd bothered to help.  Who needs to put themselves in a situation like that?

But a funny thing has been happening. There are good people out there with cameras, taking interesting shots, and it's fun again for me, now that I know how to sidestep and laugh off the inevitable keyboard rage that happens in large Facebook groups. So when I stumbled on two photographs submitted by Kimberly Nancarrow to "What's This Bird?" (the American Birding Association's FABULOUS  bird ID page),  I sat up and took notice. Over 48,000 members strong, this page is a potent way to introduce people to the joys of bird identification.

Kimberly had photographed a mystery bird sitting on the back of a whitetail doe, and that got my attention. I love seeing birds and mammals interacting.

The pair was photographed in the middle of a soybean field in Altmont, Michigan, on July 27.

Though the photos were taken at a great distance, I knew immediately what the bird was. 

There was quite a bit of disagreement among the others commenting, and what was interesting to me

was thinking about how I had known what it was right off the bat. Why wasn't it so obvious to the others?

I started thinking about how I'd arrived at my ID. I decided to deconstruct my thought process and see if I could elucidate things. Because even though I knew it instantly, there had to be a series of clues I'd picked up on, and I wanted to know what they were.

 I didn't want to do that analysis on the Facebook page, because I was afraid my effort would go to waste. So I decided to do it here. 

There seemed to be two camps: Team Starling and Team Eastern Phoebe. I was firmly on Team Starling, and here's why.

The first has to do with phenology, my field experience, and situational awareness. It's late summer, the time of year when  starlings perch on large mammals. This I knew, from my photo salon in September 2019 with a little herd of Angus crosses and their starling attendants. 

You see, in late summer the face flies and deer flies build up to plague proportions, and the starlings are happy to get rid of some for the cattle. I wrote the behavior up for my True Nature column in Bird Watcher's Digest Jan/Feb 2020 issue. I called the piece "American Oxpeckers."

So that was the first tool in my belt that perhaps the Team Phoebe folks didn't possess: knowing that starlings sit and forage for flies on large animals. 

I realized from the start that the mystery bird was showing far too much leg, and too robust a set of legs, to be a phoebe. You just don't see, or perceive, flycatcher legs at a distance. I can immediately see a good pair of legs on this bird.  To my eye, it could only be a starling. 

I also perceived that it was much too large to be an eastern phoebe. But I needed to be able to prove that was true. There had to be a way. I wasn't sure how, but I dove in anyway.  First, I traced Kimberly's photo and measured the bird, then the doe's ear. They were almost exactly the same length!

Now I needed to know how big a doe's ear might be in real life. That way, I could extrapolate, and say how big the mystery bird was. How to do that?

I happen to have a number of deer skulls in my studio that I've picked up over the years. I grabbed the biggest doe skull, since the doe in Kimberly's photo looked like a full grown one to me. This is not a skinny yearling.

I traced the skull's outline, then fleshed it out a bit. 

Before adding the ear, I measured the length of my deer's head, then measured the head of the deer in Kimberly's photo.

The deer in the photo had a 41 mm. skull with a 30 mm. ear. My skull measured 305 mm long, so I set up a simple proportion to figure out how long its ear would be.

skull length in photo  41  = 305    skull length in my drawing
ear length in photo      30       x      ear length in my drawing


I multiplied 30 x 305, then divided by 41 to get X, the ear length in my drawing. X turned out to be 8.75"

So I added an 8.75" long ear to my sketch, done from the actual skull. Now I knew how long a real doe's ear is!

Now it was time to hit the books and see how long a phoebe is, relative to a starling. David Sibley says an eastern phoebe is 7" long. I noted with satisfaction how short and delicate its legs were in Sibley's painting.

Now for the starling. Oh, look! A starling is 8.5" long! Well, my my my. That's about the same length as a doe's ear! 

Boom. Between its robust, visible legs, its potbellied profile, and its size relative to the doe's ear, this bird can only be a European starling. 

The last cool thing I noticed was the fact that Kimberly's mystery bird was dark overall, with some pale areas around the face. That works for a juvenile starling in late July. Look at these September starlings--juveniles, with just a bit of pale juvenal plumage around the head. 

Meanwhile, back in the group discussion, there were people on Team Starling flatly stating that phoebes don't sit on animals. Well, I have been studying phoebes for years, and have even raised two from babies, and I've never seen them sit on animals.  But I would never flatly state that they never do it. How would anyone know that? It's so important to be kind. It's even more important to avoid asserting something you don't know to be a fact from direct experience or solid research.

Moderator Tim Kalbach (Team Starling, but stirring the pot) contributed this photo by Chuck Holliday, taken July 22, 2019 and found on Flickr:

It's an eastern phoebe sitting on a whitetail, catching deerflies. Cool!!

I love it!! Humans can always be wrong. Birds and animals, not so much. Animals have no egos to get in the way of their truth.

 Look how much bigger the bird below appears relative to the deer, than the phoebe above. Look, too, at how you can see the thighs and legs on the starling below, but not on the phoebe, above. You can barely perceive the phoebe's legs at all, because they're so fine and short. The phoebe's belly practically contacts the deer's rump. And the contrast between dark upperparts and pale underparts is obvious on the phoebe, but totally lacking on the starling. So there's that...

I've had lots of fun proving the veracity of my ID, even if it was only for myself. Perhaps this torrent of fact-based information has won over some Team Phoebe folks, but I don't really mind either way. I like to base my ID's on facts, not opinion. I love to dive inside and see the deductive reasoning contained in a split-second judgement of bird identification. Walking through the facts here seemed like a tiny strike for the scientific process. I look forward to the day that science and fact-based reasoning re-ascend the pedestal.

I'm going to try to make sure I enjoy belonging to social media groups going forward--dip in and out, grab a fly here and there, help when I can, learn something new whenever possible, and fly off when I can't. I wish the same for you.

Thanks to the American Birding Association, page moderater Tim Kalbach, and especially to photographer/birder Kimberly Nancarrow for permitting the use of her photos. Bird on! and keep your eyes open and your camera ready.