FAMILY ACCIPITRIDAE 225 



and gracefully. The top of the head at such times often appears 

 almost white in the rays of the rising sun. This is one of the hawks 

 (known collectively to the countryman as bebe humo) that follows 

 grass fires to feed on large insects and lizards flushed, killed, or 

 injured by the flames. These, with rats and mice, seem to constitute 

 the principal items of food. Birds, except for an occasional aggres- 

 sive kingbird or fork-tailed fly-catcher, pay little attention to them, 

 and so it would appear that they are not active in molesting them. 



The Penards (Vog. Guyana, vol. 1, 1908, p. 391) describe the nest 

 in Surinam as made of sticks and twigs, placed in trees at eleva- 

 tions ranging from high to low. The one or two eggs in a set are 

 described as white with a few reddish-brown spots and blotches. An 

 egg that I saw in the possession of Dr. Carlos Lehmann, collected at 

 Maicao, in the Guajira Peninsula of Colombia, April 15, 1941, before 

 it was blown was light blue, with a few small scattered spots of light 

 cinnamon. Schonwetter (Handb. Ool, pt. 3, 1961, p. 163) gives 

 variation in the measurements of 15 eggs as 55.5-64.0x46.0-48.2 mm. 



As a species this bird ranges in open country from western 

 Panama, Colombia, and Venezuela south to Argentina. No differ- 

 ences in color are evident when specimens of similar age are com- 

 pared, but in the far south, in northern Argentina, the birds are 

 appreciably larger. There has been some uncertainty regarding this 

 since an occasional specimen of large size has been taken in the more 

 northern parts of South America, but these I believe are winter 

 migrants from the southern limits of the range, as they stand out 

 in size among those that appear to be resident. As an example of this, 

 10 specimens from northern Colombia from Bolivar, Magdalena, 

 and the Guajira have wing measurements of 379 to 403 mm. One 

 that I shot at Maicao in the Guajira on April 14, 1941, in the same 

 area in which I secured two of the smaller birds, has the primaries 

 worn at the tip but still measures 418 mm. The date represents the 

 nonbreeding period in the far south, and I regard this bird as a 

 migrant of the following form. 



The southern race, Heterospizias meridionalis rufulus (Vieillot), 

 with wing 418 to 452 mm., on the basis of present data is the breeding 

 race from southern Paraguay and Rio Grande do Sul, Brazil, to the 

 provinces of Cordoba and Santa Fe, Argentina. In the northern 

 subspecies, Heterospizias m. meridionalis, which ranges from Panama 

 south to Bolivia, northern Paraguay, and southern Brazil (north of 

 the southeastern state of Rio Grande do Sul) the wing measurement 

 ranges from 379 to 412 mm. Intergradation comes apparently in 

 northwestern Argentina, from Tucuman northward, and in central 



