23 
Key 
Figure 1 
Plumage areas of a typical bird. 
Superciliary L/ne 
I. Feet Fully Webbed — Two or three complete webs to each foot 
A, Toes, four, 
a, Tarsus flattened. 
Loons 
Figure 2 
... p. 39 
b, Closed wing longer than tail, except in some Jaegers (Figure 3) 
and Terns (Figure 5), in which the rule only holds if the greatly 
elongated central tail feathers of the former or the outer ones 
of the latter are disregarded. Bills are shown. 
Long-winged Swimmers — Gulls, Terns, Jaegers 
p. 48 
