BIRDS OF NORTH AND MIDDLE AMERICA 237 



than claw of hallux, gradually and rather strongly decurved from base, 

 the maxillary unguis moderately produced, rather long, moderately 

 to distinctly acute; maxillary tomiimi always more or less sinuated 

 (a more or less prominent convexity behind the anterior (postunguinal) 

 concavity); cere moderately large to large, broad on top (especially 

 toward base), its length on top equal to about three-fifths to nearly 

 three-fourths the length of culmen, its anterior edge distinctly sinuated 

 (convex or vertical in front of nostril, receding and more or less con- 

 cave below) ; nostril obliquely oval, ovate, or w^th anterior end nar- 

 rower (sometimes pointed), but somewhat variable in outline. Wing 

 relatively long and pointed, the longest primary exceeding distal 

 secondary by a little less than one-third to much more than two- 

 fifths the length of wing; fourth, or third and fourth, primaries longest, 

 the first equal to tenth to longer than seventh; inner webs of three to 

 four outer primaries abruptly emarginated. Tail less than half to 

 three-fifths as long as wing, its tip slightl}^ to much rounded. Tarsus 

 less than one-fifth to one-fourth as long as wing, a little more than one- 

 third to more than half as long as tail, variable as to relative thickness, 

 the upper portion feathered in front for one-third to a little more than 

 half its length, the acrotarsium and planta tarsi each with a single 

 series of broad transverse scutella; middle toe decidedly less to much 

 more than half as long as tarsus; outer toe decidedly to much longer 

 than inner toe, extending to or beyond middle of third phalanx of 

 middle toe; hallux about equal to or shorter than inner toe, its claw 

 equal to or (usually) longer than the digit; claws moderate in size and 

 curvature, acute, distinctly graduated, that of outer toe usually about 

 two-thirds as long as that of hallux (three-fourths as long in B. abbrevi- 

 atus, only three-fifths as long, or a Httle less, in B. borealis). 



Plvmage and coloration. — -Plumage moderately full and compact, 

 that of thighs elongated, forming very distinct "pantalettes"; loral 

 region densel}^ bristled; primaries and rectrices moderately rigid. 

 Coloration extremely variable, but young always conspicuously 

 difi'erent from adults. 



Range. — Nearly cosmopolitan, but wanting in the Indo-Malayan 

 and Australian regions and Oceania. (Many species, nine in North 

 and Middle America.) 



BUTEO JAMAICENSIS BOREAUS (Gmelin) 



Eastern Red-tailed Hawk 



Adult (sexes alike). — 'Top of head, auriculars, cheeks, occiput, nape, 

 scapulars, and interscapulars fuscous margined with cinnamon-brown 

 to russet, these edges broadest and most conspicuous on the nape and 

 anterior interscapulars; sometimes nearly equally so on the hind crown 

 and occiput and disappearing on the posterior interscapulars and 



