FAMILY ACCIPITRIDAE IQQ 



BUTEO NITIDUS BLAKEI Hellmayr and Conover: Gray Hawk; 

 Gavilan Oris 



Figure 41 



Buteo nitidtts blakei Hellmayr and Conover, Cat. Birds Amer., pt. 1, no. 4, Aug. 

 1949, p. 160. ("Pozo del Rio Grande" = El Pozo de Terraba, 150 meters 

 elevation, Costa Rica.) 



Distinguished in the adult by dark bands on the light gray back, 

 and the gray-banded under surface. 



Description. — Length 370 to 420 mm. Adult, upper surface light 

 gray, paler on crown and hindneck, marked abundantly with rather 

 narrow bands of darker gray, and with shaft lines of black; tips of 

 primaries black, and of secondaries white ; upper tail coverts and 

 lower rump feathers black, tipped with white ; tail black, with a broad 

 subterminal band and narrow tip white, in some individuals with 

 another band of white above the center ; throat white ; side of head 

 grayish white, marked obscurely with pale gray ; lower surface of 

 body, including the sides and axillars, white, barred heavily with 

 neutral gray; under tail coverts white; under surface of wing white, 

 changing through grayish white to dark neutral gray on tips of pri- 

 maries, with widely separated, narrow bars of neutral gray on the 

 under wing coverts, as well as on the flight feathers. 



Immature, crown and sides of head cream-buff to cinnamon-buff, 

 more or less streaked with fuscous ; above fuscous with the feathers 

 edged with russet, more heavily on the wing coverts, which are 

 blotched basally with white and rufous brown ; primaries black at tips, 

 pale rufous barred with black and with blackish brown shafts else- 

 where ; secondaries tipped with cinnamon ; upper tail coverts light 

 buff; tail black tipped with white, barred with 3 paler bands of 

 brownish gray ; below cinnamon-buff, streaked and spotted broadly 

 with brownish black ; tibia and under wing coverts cinnamon-buff ; 

 under surface of primaries and secondaries pale pinkish buff, barred 

 narrowly with dull black. 



The pattern of the immature in life suggests that of the immature 

 broad- winged hawk, but the markings on the lower surface are much 

 heavier, and the upper surface is decidedly black. Usually the crown 

 is much paler, though in some it is heavily streaked. 



A male in immature dress taken near Armila, San Bias, March 1, 

 1963, had the colors of the soft parts, as follows: Iris light brown; 

 cere and gape light honey yellow; side of maxilla at gape, lower half 

 of mandibular rami, and extreme base of gonys light green ; rest of 

 maxilla and tip of mandible black ; middle of mandible dull neutral 

 gray ; tarsus and toes bright yellow ; claws black. 



