Date: 2/26/17 11:12 am
From: Chris Benesh <cdbenesh...>
Subject: Re: [AZNMbirds] Sam Lena Waterthrush
While I would be the first to say that waterthrush ID is not obvious in this instance, I do think that we are dealing with a single Northern Waterthrush here based on the images posted to eBird. There are several ways to approach waterthrush ID, and different birders put different weight on various methods and pointers. My own methodology works something like this: What is the pale ground color? Is it either clean white or very pale yellow throughout (Northern) or does it have buff colored sides that contrast with the rest of the underparts and particularly the color of the eyebrow (supercillium). If there is obvious contrast (e.g. white supercillium and buff sides), the bird is a Louisiana. Usually that is enough because the other features will fall into place. The thicker, more widely spaced underparts streaking of Louisiana becomes apparent, versus the narrower, more defined streaking of Northern. Flared eyebrows and bubblegum pink leg features don’t always work really well for me, but they are supporting characters. Same with throat streaking (can be really faint on Northern, though on my computer screen I can make out some short streaking in the throat of the Sam Lena bird). Voice is a useful distinction for these two with a bit of practice. LOWA has a quick, smacking quality to their call, lacking much tonality. NOWA has a lower pitched harder chink sounding note that is a bit more drawn out and tonal.

Looking at all of the images posted to eBird of the Sam Lena bird, I see a waterthrush that I would call a yellow-type Northern, that is, there is faint yellowish wash to the underparts and to the eyebrow. To get a sense of what I’m talking about compare this shot of Brian’s Sam Lena bird: https://macaulaylibrary.org/asset/49000271#_ga=1.153645496.1451393783.1427170107

to Ken’s shot of the Sasco Road LOWA: https://macaulaylibrary.org/asset/48693321#_ga=1.85611417.1451393783.1427170107

See how the eyebrow really POPS out on the Sasco Road bird? Having said all that, lighting, camera settings, photo processing can all affect how obvious these differences appear in photos. But looking at a large series of images, I see this as a Northern.

Chris


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Chris Benesh
Tucson, Arizona
<cdbenesh...>

Field Guides - Birding Tours Worldwide
www.fieldguides.com


"Minds are like parachutes. They only function when they are open."
James Dewar
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> On Feb 26, 2017, at 10:35 AM, Richard Carlson <rccarl...> wrote:
>
> Brian Nicholas pictures show large bill and unstreaked chin. That makes it a Louisiana, but leg color and supercilium look Northern. Which is it? Two different birds?
>
> Richard Carlson
> Full time birder, part time economist
> Tucson & Lake Tahoe
> Sent from my iPad
>
>> On Feb 26, 2017, at 8:23 AM, Gary Rosenberg <ghrosenberg...> wrote:
>>
>> Hi all,
>>
>> Kurt and Cindy Radamaker, and I just saw and photographed the waterthrush at Sam Lena Park, and it is an obvious NORTHERN- in case you were thinking of chasing it.
>>
>> Good birding,
>>
>> Gary
>>
>> Sent from my iPhone
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>
> Home Page: https://list.arizona.edu/sympa/info/aznmbirds
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