FALCONID^E — THE FALCONS. 
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whitish ; lower parts transversely barred with brown on the breast and 
sides, and sometimes on the abdomen. A white gular patch, and jugular 
collar, with a brown band between them. Legs, crissum, anal and femoral 
regions, always immaculate. Nest in excavation in the ground; usually 
those made by mammals, sometimes by themselves. 
Primaries with broad regular bars of ochraceous-wliite on both 
webs ; primary coverts with large spots of the same. Brown markings 
on the lower parts regularly transverse, and not ragged. White spots 
on the upper, parts much less than the brown in extent. 
Wing, .6.40 - 7-00 ; tail, 3.00 - 3.30 ; culmen, .50 - .60 ; tarsus, 
1.50-1.70; middle toe, .80. Outer tail-feathers and inner 
webs of the primaries with the white less! in extent than 
the brown (never continuous along outer webs of the pri- 
maries). Hab. Middle America, and Western Province of 
North America. ( Burrowing Owl.) . . . var. hy pog cea. 
Family FALOOJNIBiE, — The Falcons. 
Genera. 
A. Nasal bones almost completely ossified, the nostril being a small orifice, with 
a conspicuous central bony tubercle ; its form nearly or quite circular, or linear 
and oblique (in Polyborus ), with its upper end the posterior one. (Page 126.) 
( Falconince ). 
1. Falco. Nostril circular. Commissure with a prominent tooth 
and notch ; lower mandible abruptly truncated and notched. 
Primaries stiff and hard, and more or less pointed, the first to the 
second longest, and the outer one or two with their inner webs 
cut, the angular emargination being near the end of the quill. 
Middle toe much more than half as long as the tarsus; claws 
strongly curved, very acute. Iris said to be generally brown 
(yellow in F. anatum , according to Richardson). Eggs very 
thickly and closely marked and mottled with brown and chocolate, 
generally nearly concealing the cream-colored ground. Nest 
usually on cliffs ; exceptionally on trees. 1 (Page 126.) 
2. Polyborus. Nostril linear, oblique, the upper end the posterior 
one ; commissure without prominent tooth nor notch ; lower man- 
dible not distinctly truncated or notched. Primaries soft, obtuse, 
the third longest, and the outer four or five with their inner webs 
cut, the shallow’ sinuation being toward the middle of the quill. 
Middle toe less than half the tarsus ; claws weakly curved, very 
obtuse. Face and cheeks naked, and scantily haired. Iris brown. 
Markings of eggs generally much as in Falco , sometimes showing 
much more of the ground-color. Nest placed on low trees or 
bushes. (Page 131.) 
12. Nasal bones very incompletely ossified, the nostril being a large, more or 
| less oval, opening, of oblique direction, its lower end being invariably the pos- 
terior one ; without a bony tubercle, and never perfectly circular. (Page 131 .) 
(Buteonince.) 
1 The statements as to the color of the iris are intended to apply only to the North American 
species. Accurate indications are still wanting for many of our Falconidce. 

