Date: 11/18/19 10:00 pm
From: ed mcv <ed.mcvicker...>
Subject: [obol] Re: Sauvie Island (Columbia Cty.)Light morph Harlan's hawk
Jack,

Your photos are great but I believe you've captured an immature western
Red-tailed Hawk (*calurus*) and not the light-morph Harlan's Hawk I saw
last week. Your checklist of characteristics seems right on for our more
typical *calurus* immature red-tail. Here is a photo
<https://www.flickr.com/photos/10665268@N04/49068019282/in/dateposted/> of
an immature western RTHA (perhaps the same individual in your photos) I
snapped just a few Reeder Rd. power poles away from the light-morph
Harlan's Hawk
<https://www.flickr.com/photos/10665268@N04/49058693762/in/photostream/>.


Two characteristics that I thought stood out about the Harlan's last week
were the tail pattern and the overall near white of the lighter feathering
on the body and head. The tail lacked the typical barring and color
uniformity that is present in many/most adult RTHAs and the Harlan's
pattern was a more smudged black & red & bright white with vertical
pattern/streaking. I thought that was quite striking and different. The
other thing that stood out to me was the strong dark/white contrast to the
face, head/nape and body feathers on the Harlan's as compared to the
browner/creamier contrast on your immature bird.

Two resources I found helpful:
Bill Clark's article
<http://www.globalraptors.org/grin/researchers/uploads/155/harlansplumagesdifferrev2-14_(1).pdf>
- a little hard to follow but it has some nice comparison Harlan's/Western
RTHA photos
Liguori & Sullivan article
<https://docs.google.com/viewerng/viewer?url=http%3A%2F%2Ffvaudubon.org%2Fwp-content%2Fuploads%2FHarlans-W-and-E-Red-tailed-Hawks.pdf&hl=en_US&urp=gmail_link>
- mentioned by Bob Archer. Quite good if a little lacking in light-morph
Harlan's photos.

Best,
Ed

On Mon, Nov 18, 2019 at 8:02 PM Jack Williamson <
<jack.williamson.jr...> wrote:

> I have more questions than answers after reviewing a few images
> (presumably) of the same bird first found by Ed McVicker then refound by
> Tom McNamara 16 November.
>
> I have labeled the following field marks for [+] and against [-] a
> Harlan's Id this evening after reviewing images captured earlier today
>
> [-] Lack of Feathered tarsi
> [+] Outer primaries appear boldly banded
> [-] Absence of a dark belly band
> [-] Patagials not larger/bolder than other species in the area
> [-] Absence of longitudinal black streaks on retrices
> [-] Forecrown not distinctly whiteish
> [+] Yellow cere
>
> Looking forward to learning what I have not seen but should have.
>
> View the full-screen slideshow for the best resolution.
>
> https://adobe.ly/346t2UI
>
>
> Jack Williamson
> West Linn, Oregon
>

 
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