Comments:

2010-14  Chihuahuan Raven
 
How different are the bills of Chihuahuan Raven vs Common Raven?  Is it possible there is some overlap in bill and bristle sizes? 
 
I found this web page - http://www.fortunecity.com/greenfield/egret/290/id139.htm .  On this web page there are 3 photos.  The first photo is a line up of 4 Chihuahuan Ravens, the second photo is a line up of 2 Chihuahuan Ravens then 2 Common Ravens, the third photo is of the same birds in photo 2.  These were the only photos I could find of Chihuahuan Raven and Common Ravens with the same profile angles.  To try to get a better idea of how different the bills are I copied the head of the top Chihuahuan Raven from the second photo on this website (2 Chihuahuan Ravens and 2 Common Ravens)  I enlarged the head and adjusted the angle to match the common (3rd bird down) but kept the aspect ratio the same.  I tried to do this in the same way Rick did with his Common Raven and the photo from the Record so I could better understand what the differences might be.

Looking at the Chihuahuan Ravens in the photos on this website it looks to me like the bills can be variable.  Chihuahuan Ravens average shorter with longer bristles but I think if you resize the birds to be the same size as commons there may be bill and bristle length overlap (long billed Chihuahuas may be similar to short billed Commons).

This web page also suggests a color difference between the Ravens - "Chihuahuans have a brown cast to the plumage, while the Commons have a gunmetal black color with more blue and purple highlights." The photos of the possible Chihuahuan Raven in this record look brownish but I am aware color can sometimes be misleading in photos.

I feel the best field mark is the White Feather Bases described as "unquestionably white bases to the feathers of the neck" in the written description.

Eric Huish
Pleasant Grove UT
poorwill_@hotmail.com
801-360-8777