Wednesday, July 28, 2010

I love to misidentify birds!

strange sparrowStrange sparrow presents a learning opportunity, Jackson Bottom Wetlands Preserve, Hillsboro, Oregon on 13 July 2010 by Greg Gillson.

 

Don't kill him! If you kill him he won't learn nothin'.
- The Riddler. Batman Forever (1995, Warner Bros. Pictures).


Thank goodness we don't get the death penalty for misidentifying birds, because I'm a repeat offender! I don't learn much if I say, "that's a robin" and my birding associate says, "yup."

However, when I make an error in identification, I spend a lot of time figuring out just exactly why and how I was fooled. I do research, ask questions, and learn....

On July 13, 2010 I was out in the back prairie at Jackson Bottom Wetlands Preserve in Hillsboro, Oregon, when a mid-sized pale sparrow flew out of the grass and up into a nearby tree.

The first thing that grabbed my attention was the buff (pale yellowish-brown) overall color, including the under parts. There was an obvious ochre (orangish-brown) color cast to the sides of the neck and upper chest. I quickly got off a couple of photos before a Song Sparrow came in and chased it away.

That orangish breast and lower face made me think of Le Conte's Sparrow or Nelson's Sharp-tailed Sparrow. But the bird I saw was not flat-headed and short-tailed as these Ammodramus sparrows. In fact, it appeared round-headed and long-tailed, about like the Song Sparrow that chased it.

strange sparrowStrange sparrow, Jackson Bottom Wetlands Preserve, Hillsboro, Oregon on 13 July 2010 by Greg Gillson.

 

The bird was obviously a sparrow. I suspected a juvenile sparrow. Two sparrows breed at Jackson Bottom: Song Sparrow and Savannah Sparrow. This bird did, indeed, have much to remind one of Savannah Sparrow.

Juvenile sparrows retain much of the head pattern of the adults, and usually show fine streaking on the chest. The head pattern of the observed bird did not match Savannah Sparrow, though.

My brief field notes were jotted down as:
Very pale. [Overall color] blonde-orange-tan. Brown lateral crown stripe, line through eye, around auriculars, mustache, and very wide lateral throat stripe. Throat buffy-orange. Thin white eyering. Obvious white upper [lower] wingbar. Thin streaks across upper breast/lower throat.
The wide lateral throat stripes and pattern on the face reminded me strongly of Song Sparrow. Some references indicated that juvenile Song Sparrows were buffier than adults. All juvenile Song Sparrows I had ever seen were dark and heavily streaked.

Nevertheless, I convinced myself that this must be a very young Song Sparrow just out of the nest, in a buffy plumage I had never seen.

After I posted photos Larry McQueen answered back that he thought it a Vesper Sparrow. Dave Irons added the following comments:
The highly restricted breast streaking, bold fanned out lateral throat stripe (malar), complete eyering and dark marking framing the auriculars all point to Vesper Sparrow. At first I wondered if it wasn't some really weird Savannah Sparrow, but there is no plumage of Savannah that shows so little streaking below.

Well, of course! How could I not come to that conclusion? The facial pattern, including the wide lateral throat stripe matches Vesper Sparrow. And the eyering? Look! "Thin white eyering" is in my description--but I ignored it. The tail is square or notched, not matching the rounded tail of Song Sparrow.

How and why did I make this mistake?

I didn't get a long look at the bird, though I could tell it was unusual. The Song Sparrow did chase it away before I had a chance to see white outer tail feather (barely discerned in the second photo). So, one reason I didn't get it right was that my view was too short in duration.

But I believe that the main cause of my misidentification was expectation. I expected any juvenile sparrow there to be Song Sparrow or Savannah Sparrow. I didn't expect anything else, so rejected the thought.

In fact, this apparent juvenile Vesper Sparrow is the first Washington County record in 12 years! This is the first and only record of Vesper Sparrow for Jackson Bottom. [Note: Jonathan Plissner reported Vesper Sparrow this year at Fernhill Wetlands in Forest Grove on May 11.]

Now the questions arise: Where did it come from? Is it nesting somewhere there on the prairie?

I will now keep my eyes--and mind--open.

3 comments:

  1. Interesting! I look forward to hearing if more turn up!

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  2. Thanks for sharing your lesson learned.

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  3. Hmmmmm~ It is not exactly like you can go back and ask the bird.... bird, what might I ask are you..?;) It is such fun to learn and also to make human mistakes, for those are the things that we make even greater in advancement in our learning, for if you see that little bird again...I bet you will know exactly what it is right off...hoping it shall not be 12 years either~

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