The color plate by Fuertes in Phillips' NATURAL HISTORY OF THE DUCKS,
1922 (Dover reprint, 1986) shows what appears to be pale nail protruding 
from
the rear toe.  All nails, front and back, appear pale.  This a large 
illustration, much
larger than in Belrose, etc.

Alas, the text of Phillips, WATERFOWL  (Madge and Burn, 1988), and
HANDBOOK of N. AMERICAN BIRDS (Palmer, vol. 2, 1976) make no mention
of nail color!!!!

Kurt Schwarz
HowCo
goawaybird at comcast dot net