18 

 Key. 



^Superciliary Line 



Fig. 1 — Plumage Abeas of a Typical Bird 



I* Feet Fully Webbed — Two or three complete webs to each foot- 



A, Toes, four. 



a, Tarsus flattened. 



Fig. 2 — Loon 



Loons p. 44. 



Fig. 3 — Jaegeb 



Fig. 4— Gull 



Fig. 5— Tebn 



b, Closed wing longer than tail, except in some Jaegers (Fig. 3) 



and Terns (Fig. 5), in which the rule holds only if the greatly 

 elongated central tail feathers of the former or the outer ones of 

 the latter are disregarded. Bills as shown. 



Long-winged Swimmers — Gulls, Terns, Jaegers p. 48.. 



