[CT Birds] Guilkford oriole

Greg Hanisek ghanisek at rep-am.com
Sat Nov 16 16:52:24 EST 2013

Amy Hopkins provided a nice series of photos of her oriole, which I think is a Baltimore. The Baltimore-Bullock's pair is easy for adult males but otherwise not so much. Dull females and immatures can be tough because they (Baltimores especially) are quite variable. Then there's always that hybrid thing hovering in the background. This is a pretty tough one, but I go first to the head/face. Bullock's females should show a shadow pattern of adult male features. That means there should be a noticeable eyeline (thin dark line running back from the eye), and the face should be pretty bright on the area of the auriculars and the supercuillium. This birds is drab on those areas (basically it's drab everywhere above the malar region). It has a pretty featureless face.   
Sibley notes that Bullock's in brightest on the malar. This bird has a bright malar, but Sibley notes that the malar is specifically bright in comparision to the paler yellowish breast on a Bullock's. On Baltimore the breast is usually more orange and brighter. Amy's bird seem to have that pattern. It's especially apparent on the image where the bird is tipping down to feed.  
Also Bullock's usually (Baltimore rarely) showes thin prongs or spikes pointing downward into the white upper wingbar (median coverts). Despite many angles in the photos, Amy's bird doesn't seem to show this.  
Bullock's usually show gray undertail coverts in combination with a gray rump. On this bird the undertail is yellowish-orange and a shot with the tail cocked seems to show that color continuing onto the rump.  
The back is grayish and it doesn't seem to be very well marked, although there is some pattern present. Either species can show a gray back, but on Baltimore the feathers often show dark centers, so this seems to be one feature on this bird that may favor Bullock's. But I'd say the preponderance of evidence is for Baltimore, probably female.  
Greg Hanisek  

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