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Ornithological Studies Presentation
Large Alcids

by Paul Guris 01/03

 
Razorbill
Thick-billed Murre
Common Murre
Bill
Deep, stout bill with white band around the middle, flattened side to side. 1st winter bill smaller but still deep, with no white band. Shortish and stout, with decurved culmen, noticeable gonydeal angle, whitish line along upper gape. 1st winter somewhat smaller, with limited white gape line. Long, straight, slender, and pointed. Warning: can occassionally show paleish gape line.
Head & Neck (winter)
Lower face white, upper dark with white rising behind eye. Dark, rough line from eye. Nape dark. Sides of neck mostly white. Lower face white, upper dark with no white above the eye. Nape and sides of neck dark. Lower face white, upper dark with white rising behind eye. Thin, clean line from eye. Nape mostly dark with white wrapping up from sides of neck.
Head & Neck (summer)
All dark with white coming to a rounded point on the foreneck. White line from bill to eye. All dark with white coming to a sharp point on the foreneck. All dark with white coming to a rounded point on the foreneck.
Upperparts
Black. Black. Often browner than the others, but varies with population and age.
Underparts
White. White. White, often with darkish streaks on flanks.
Underwing
“Wingpit” white. “Wingpit” white. “Wingpit” dusky.
Swimming Profile
Large bill, often tilted up. Large head and thick neck. Long tail often cocked up. Short stout bill usually held level. Blocky head, “neckless” look, and short rear end. Long, thin bill sometimes held up. Small head, thin neck, and short rear end.
Flight Profile
Streamlined body, with thick neck, and blunt front end. Long pointed tail covers the feet. Hunchbacked body, “neckless” look, with bill pointed slightly down, and rear end “dumpy”. Short, blunt tail usually does not cover feet. Slightly hunchbacked body, thinner head and neck than Thick-billed, rear end “dumpy”. Short, blunt tail usually does not cover feet.
Rump
Much white showing on top. Much white showing on top. Little white showing on top.
Spring Molt
Not sure. Seems to fill in across chest first and onto throat last, often (always?) creating a partial breast band. Dark fills in evenly. Fills in with spotting on throat and chin. Shows vestiges of winter pattern well into its molt.

 


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