Date: 2/27/17 6:07 am
From: Phil Jeffrey <phil.jeffrey...>
Subject: Re: [AZNMbirds] Sam Lena Waterthrush Follow-up
:: they essentially occur along rivers and streams with running water

As an East Coast birder who sees both waterthrushes each year, I'd like to
chip in on this.
We see Louisianas next to still water including muddy puddles a significant
proportion of the time in Central Park (NYC) on migration and I've seen
them in TX in the same context. I would not use this as an ID factor.
Northerns are probably more prone to wander away from water - wet lawns and
shaded cover, but that's also biased by Northerns being significantly more
frequent through NYC.

Amongst the other factors people have listed - which all seem reasonable to
me - I haven't seen mention of one that may be useful - Northern bobs in a
different way than Louisiana waggles. Northern bobs mostly it's tail with
relatively little movement of the body beyond (head-side) the legs, closer
to Palm or Prairie:
https://www.youtube.com/watch?v=VcoF12ILFEw
- this bird also being useful as a pale NOWA for ID comparisons

In contrast a Louisiana is much more articulated, and the legs bob as well,
with the whole body rotating about an axis in the breast. Really only the
head remains still.
https://www.youtube.com/watch?v=Y4I7ZTzywIc
I didn't pick this one because the LOWA was feeding in still water, but it
conveniently does go back to my original point.

I use the motion as one of my ID criteria, behind supercilium and flank
contrast, leg color (spring only), call note and streaking density/shape.

Cheers
Phil Jeffrey
Princeton NJ

On Sun, Feb 26, 2017 at 2:48 PM, Gary Rosenberg <ghrosenberg...>
wrote:

> Thanks Chris for your detailed analysis. One other factor I would mention
> is habitat. I don't want to say "never", but I ca not think of a single
> LOWA record from AZ from a pond - they essentially occur along rivers and
> streams with running water. This is also true for them wintering in the
> Tropics. Given that this bird was at a small pond with a mud edge should
> have made people question the ID.
>
> Gary
>
> Sent from my iPhone
>
> Home Page: https://list.arizona.edu/sympa/info/aznmbirds
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