KEY tO THE WATER BIRDS OF FLORIDA. Ig!l 
Famity LARIDJE. Gutis anp TERNS. 
Suspramity LARINE. GuLtis. 
Genus LARUS Linn. 
LARUS MARINUS Zinn. 
Great Black-backed Gull. 
Adult in summer: Whole back dark slate color ; outer primaries black, with tips and termi- 
nal spots of white; head and under parts white. 
Adult in winter: Headand neck streaked with gray. Immature birds are mottled dusky and 
buff; head and neck streaked; tail with narrow subterminal band; a very large gull. 
Length, 29; Wing, 18: Tail, 8: Tarsus, 2.70; Bill, 2.40. 
Coast of North America south to South Carolina; accidental in Florida. 
Breeds from Northern Maine northward. The nest is built on the ground ; 
the eggs are usually two, pale brown, marked with chocolate brown. 
A specimen of this gull was shot near St. Augustine during the winter 
of 1894-5. 
