308 BUTEO BOREALIS. 



an event was quite uncommon as these birds usually breed much further north, only visit- 

 ing New England late in autumn and departing early in spring. 



FAMILY IV. BUTEONID^l. THE BUZZARD HAWKS 



The sternum is short, wide, and nearly equal in width to the length cf the coracoids, but 

 the scapular process of the latter does not meet the furcula. Marginal indentations, two, in- 

 closed. 



This family, in our section, is represented by two genera. The manubrium is mod- 

 erately well developed, abruptly truncated, and not forked. The furcula is stout, much 

 flattened by lateral expansion, wide and thick near the base which is rounded and not pro- 

 duced into a point. The terminal expansion is rather small and the furcula near it is only 

 slightly contracted and furrowed above, and is bent downward to a point, closely approxi- 

 mating the top of the manubrium. The marginal indentations, although varying in size 

 with age, are always inclosed. Bill, strong, well-curved, with the cutting edge of upper 

 mandible slightly lobed. The tarsus is short, stout, and naked to the heel behind, but 

 more or less feathered in front. The toes are stout, with strong, well-curved claws. The 

 wings and tail are moderately long, the former are not pointed and the latter is usually 

 slightly rounded. 







GENUS I. BUTEO. THE NAKED-LEGGED HAWKS. 



GEN. CH. Sternum, rather narrow and lony, only bciny about as wide as it is hiyh, including the keel. Tarsus, not 

 feathered to the toes in front. 



There i-s quite a thick sterno-trachealis, a stout bronchialis, but no other laiyngeal muscles. The trachea is a little flat- 

 tened throughout. The oesophagus is dilated near the middle into quite a large crop, and the walls are very thin. The pro- 

 ventriculus is rather large, with quite small, simple, oval glands, arranged in a zonular band which measures from '75 to 

 I'Oli in width. The stomach is somewhat globular in form, with quite thin walls, lined with a soft membrane. The f>ld 

 of the duodenum is long, inclosing a small, irregularly formed pancreas which only occupies a short portion of its entire 

 length. The coeca are very small. Both lobes of the liver are about equal in size, and the heart is large and pointed. The 

 spleen is an oval shaped body situated on the proventriculus. There are six species within our limits. 



BUTEO BOREALIS. 



Red-tailed Havrk. 

 Buteo borealis VIEILL. Nouv. Diet, d' Hist. Nat., IV; 1816, 478. 



DESCRIPTION. 



Sp. CH; Form, robust. Size, large. Sternum, stout, but rather narrow; marginal indentations quite large. Tongue, 

 quite fleshy, rounded at the tip and slightly bifid. Tarsus, feathered in front for more than half its length. Four outer 

 quills are incised on the inner webs. Sexes, similar in color. 



COLOR. Adult. Sides of head and entire upper surface, excepting tail and outer portion of tail coverts, dark-brown, 

 with the feathers edged with whitish and yellowish-rufous; barred on scapularies with whitish and on the remainder of 

 wings with dusky. Tail, cinnamon-red, white at extreme base and tip, and provided with a subterminal band of black. 

 Outer portion of upper tail coverts, white, barred with cinnamon-red and dusky. Beneath, yellowish-white everywhere, 

 deepest on the tibia, heavily streaked on throat with dusky, across breast with reddish-brown, where the spots frequent- 

 ly become so broad as to form a band; there are also broad streakings of dusky-brown in a band across the middle of the 

 body, and the remainder of under portions, excepting under tail coverts, are finely streaked with reddish-brown. There is 

 a broad line of dusky-brown on the cheek. 





