FAMILY ACCIPITRIDAE 197 



It was my impression that the bird had come over from that area 

 for a time attracted by the soaring flock. 



In the air the adults appear white underneath, with dark head 

 sharply outlined from the lower foreneck, dark wing tips, and a dark 

 band at the end of the tail. It would be difficult if not impossible to 

 distinguish those in dark stage of plumage from other species of 

 black colored hawks. 



The Spanish name, gavildn teje, is given in imitation of the high- 

 pitched double-noted, accented call, uttered often as the bird circles 

 high in air. 



While there is no description of the breeding of this hawk in 

 Panama, elsewhere in the range of this race, which extends from 

 southern Texas through Mexico and Central America to northern 

 Colombia and Venezuela, the nest is a structure of sticks placed in 

 low trees in open country. Bent (U. S. Nat. Mus. Bull. 167, 1937, 

 p. 218) says that the set includes 1 to 3 eggs, in color dull white to 

 pale bluish white, some spotted with dull brown, clay color, or buff 

 and some plain, without markings. Measurements vary from 52.7- 

 65x42.2-50 mm., with the average 58.9x46.5 mm. The downy 

 young, with the body dull buffy brown, whiter underneath, becoming 

 dull sepia on the head with a dull black mark through the eye, are 

 quite different in appearance from those of other species of the larger 

 hawks. 



BtTTEO ALBONOTATUS Kaup: Zone-tailed Hawk; Gavilan Negro 



[Buteo] albonotatus Kaup, Isis von Oken, 1847, Heft 5 (May), col. 329. 

 (Mexico.) 



Black, with under surface of wing banded with white. 



Description. — ^Length 450 to 550 mm. Adult, black, with many of 

 the feathers white, or partly white, basally; some individuals with 

 a wash of slate color on back and breast ; lores and forehead white, 

 with blackish shaft streaks ; tail, above tipped narrowly with white, 

 and banded with 5 or more indistinct gray bands ; below, grayish to 

 white, banded narrowly with neutral gray ; under surface of primaries 

 and secondaries neutral gray, barred with white ; under wing coverts 

 black. 



Immature, sooty brown to black, spotted irregularly with white 

 on lower surface ; tail with numerous bands. 



In the hand it may be noted that four outer primaries are distinctly 

 notched at the tip. The other species of the genus Buteo found in 

 Panama that are black or dark-colored below have only 3 of the 

 outer primaries cut on the inner margin. 



