Another really good field mark for both males and females is the shape of the white tips on the median coverts (the upper wing bar).  In Bullock's Oriole the wing bar has a sawtooth upper edge while Baltimore Oriole exhibits a smoother edge. This difference is well illustrated in both Sibley and National Geographic guides.

Paul O'Brien
Rockville, Mont. Co., MD

On Nov 25, 2009, at 12:11:51 PM, "Jeff Shenot" <> wrote:

From:   "Jeff Shenot" <>
Subject:    Re: [MDOSPREY] Bullock's Oriole in Montgomery
Date:   November 25, 2009 12:11:51 PM EST
To: 
From what I read, another good field mark for both male and females is in the outer tail feathers the orange edges extend to the base of the feather by the rump (on Baltimore the edge is black at the base of feather near the rump). In the photos on the internet I looked at, whenever there is a good view of the tail (from above) this seems to be very consistent. I wonder how close you have to be to see this field mark.

Jeff Shenot
Croom MD