[Tweeters] MERLIN - Possible Boreal Subspecies - Snoqualmie

johntubbs at comcast.net johntubbs at comcast.net
Sat Oct 9 11:29:51 PDT 2010

Hi everyone,

We had another Merlin visitor to our 'raptor snag' this morning for about ten minutes and got to look at it through the scope for most of that time.  This was clearly a different individual than the one(s) I saw and reported earlier, in that this bird was very dark.  My first thought on subspecies was Black/Pacific, but not being a falcon expert I came in and studied the Merlin section in Wheeler's book after the bird flew off.  In reading through his descriptions (and looking at the images), it seems to me now that this bird was probably a Boreal/ columbarius subspecies bird.  The primary reason for this tentative conclusion is the supercilium.  The bird this morning had a clearly defined and long light colored supercilium extending from the forehead a good percentage of the way to the back of the head, definitely over the auriculars.  Plate 535, page 452 in Wheeler is a ringer for the bird I saw.  Here are two applicable quotes from Wheeler:

'Black' Merlin

"...at most there is a very small supercilium patch over the eyes."  p. 439.

'Boreal'/ columbarius

"The long thin supercilium connects with the white forehead and extends over the eyes and auriculars."  p. 438.

I was not familiar with other differentiating field marks when I was watching the bird, so some other keys noted in Wheeler were not observed (or observable based on distance and a branch obscuring leg feathers, etc.). 

Black, Taiga and Boreal are all subspecies that occur in this area per Wheeler, and I do know that there is some hybridization documented. 

To our raptor experts out there, how common is the Boreal subspecies relative to the other two, and is the prominence of the supercilium alone sufficient to make a call?

John Tubbs

Snoqualmie, WA

johntubbs at comcast.net

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman2.u.washington.edu/pipermail/tweeters/attachments/20101009/26ebb126/attachment.html

More information about the Tweeters mailing list