Orange-crowned warbler (photo by Dan Arndt)
In good light with a clear view these two warblers don’t look alike.
Female yellow warbler (photo by Dan Arndt)
But in poor light and partially hidden by leaves a fast-moving yellowish fall warbler without wing bars can be … confusing.
Last Sunday one of these birds had me stumped. Without a camera to take its picture, how could I find out what it was?
Using a technique I learned from Chuck Tague, I wrote down what I saw as if I was going to draw the bird.
“Long, all-yellowish warbler with blank face, round head, blunt beak, no wing bars, no stripes.” (Wish I’d seen the tail and leg colors.)
With this note and several field guides I was able to figure it out at home.
“No wing bars, no stripes” narrowed the field considerably.
By “all-yellowish” I meant pale yellow from throat to undertail with drabber, darker yellow on back, wings, head. The light made the bird look very drab. Lots of book-searching finally pointed to two possibilities: an orange-crowned warbler or a female yellow warbler. Range maps indicate both can occur now in western Pennsylvania so I had two viable candidates.
“Long” and “round head” can be deceiving because a squat, no-neck warbler might stretch out its neck to see me but together they lean toward yellow warbler.
“Blank face” is an excellent hint, not just a patternless face but actually flat looking. The orange-crowned warbler has tiny white accents above and below its eyes that give its face topography even if you don’t see the accents. Yellow warblers are known for their plain blank faces.
“Blunt beak” describes the yellow warbler’s stout bill rather than the orange-crowned’s sharply pointed bill.
So what did I see? Most likely a yellow warbler.
Oh well. An orange-crowned would have been nice.
The key is: Write everything down. Pretend you’re going to draw the bird when you get home.
(photos by Dan Arndt, Creative Commons license on Flickr. Click on the images to see the originals. Dan lives in Calgary and writes for two blogs: Birds Calgary and Bird Canada.)
p.s. I used the The Warbler Guide by Tom Stephenson and Scott Whittle to figure this out. It’s excellent for deciphering confusing fall warblers.