NORTH AMERICAN BIRDS. 
a. Sides of the head densely feathered close up to the eyelids. 
3. Pandion. Outer toe reversible ; claws contracted and rounded 
on their under surface, and not graduated in size. Wing long, 
third quill longest ; outer four with inner webs emarginated. Tail 
rather short, rounded. Iris yellow or orange. Eggs generally 
much as in Fcilco ; usually blotched with dark wine-color; the 
ground often tinged with the same. Nest usually on trees, 
occasionally on cliffs, especially in Europe. (Page 131.) 
4. Hauclerus. Outer toe not reversible; claws not contracted or 
rounded on under side, and graduated in size. Wing long, third 
quill longest ; outer two with inner webs sinuated. Tail excessively 
lengthened and forked, the lateral pair of feathers more than 
twice as long as the middle pair. Iris reddish-brown (Dresser) 
with blue edges (Aud.) Eggs rather thickly blotched with dark 
brown, especially at larger end. Nest on trees. (Page 132.) 
b. Sides of the head with a more scantily feathered orbital space, with a 
projecting superciliary “ shield ” covered with a naked skin. 
* A well-developed membrane, or “ web,” between the outer and mid- 
dle toes at the base, 
t Tarsus about equal to the middle toe. 
§ Claws short and robust ; two outer quills with their inner webs cut. 
5. Ictinia. Commissure irregularly toothed and notched; front 
of tarsus with transverse scutellae. Tail emarginated ; third quill 
longest. Iris blood-red. Eggs white. Nest on trees. (Page 132.) 
6. Elanus. Commissure without irregularities ; front of tarsus 
with minute roundish scales. Tail double-rounded ; second quill 
longest. Iris brownish-red. Eggs sparsely spotted. Nest on 
trees. (Page 132.) 
§§ Claws long and slender ; five outer quills with inner webs cut. 
7. Rostrliamus. End of bill bent downward, with a long pendent 
hook ; inner edge of middle claw slightly pectinated, or serrated. 
Tail emarginated ; third or fourth quill longest. Eggs blotched 
quite thickly and uniformly, on dead white, little apparent 
ground. Nest on low trees. (Page 133.) 
ft Tarsus very much longer than the middle toe. 
IF Front of tarsus unfeathered, and, with the posterior face, covered 
with a continuous series of broad transverse scutellae. 
a. Form very long and slender, the head small, the tail and legs long and 
claws excessively acute ; bill weak, compressed, very high through the 
base, the culmen greatly ascending basally, and the cere much arched ; 
commissure usually with a very prominent “ festoon.” 
8; Circus. Face surrounded by a “ ruff” of stiffened, differently 
formed feathers, as in the Owls. Tarsus more than twice as long 
as the middle toe. Wing very long, hardly concave beneath ; 
third to fourth quill longest ; outer four with inner webs sinuated. 
Iris probably brown in young, yellow in adult. Eggs white; 
occasionally obsoletely blotched with brown. Nest on ground. 
(Page 133.) 
9. Nisus. Face not surrounded by a ruff. Tarsus less than 
twice as long as the middle toe. Wing short, very concave 
beneath, the outer quill much bowed ; third to fifth quills longest ; 
outer five with inner webs sinuated. Eggs white in some species, 
