100 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



noiseless, so that the downy margins on the flight feathers seem to 

 serve to deaden the sound of the wings. In life the facial niif was 

 almost as prominent as in the marsh hawk. 



Swann^^ has described a subspecies from Sarayacu, Ecuador, as 

 huckleyi on basis of small size. Specimens available agree more or 

 less in measurement throughout the entire range of the bird, so 

 that it is possible that this bird from Ecuador, with a wing measure- 

 ment of only 217 mm., may be an aberrant specimen or may belong 

 elsewhere. 



My skin from Paraguay is a male (apparently in its second year) 

 of the extreme of the rufescent phase for this species. The dorsal 

 surface is entirely warm brown in color, with the transverse lighter 

 markings on wings and back more definitely indicated than is usual. 

 A few dusky feathers are in evidence on the crown and back. It 

 measures as follows: Wing, 246; tail, 248; culmen from cere, 18; 

 tarsus, 81.5 mm. 



SPIZIAPTERYX CIRCUMCINCTUS (Kaup) 



Earpagus circumcinctus Kaup, Proc. Zool. Soc. London, 1851 (pubL Oct. 

 28, 1852), p. 43. (" Chili "= Argentina.) 



This rare hawk was found in small numbers near Victorica, 

 Pampa, on December 23, 27, and 28, where three specimens were 

 secured, a. pair on December 23 and an adult male on December 28. 



The birds frequented the larger growth of woodland in this 

 region, usually where the forest of heavy-limbed, stocky trees was 

 fairly open. To avoid the intense rays of the sun, they chose shaded 

 perches in such trees as the calden, where the foliage was confined 

 largely to the tips of the branches and did not obscure the outlook 

 below or at the side. Attention was drawn by the querulous whining 

 calls of these falcons, similar to a note of the brown thrasher, but 

 given in a much louder tone. At times the birds, rather tlian fly, 

 hopped agilely through the limbs to place a screen of branches 

 between themselves and the observer. Their flight was direct, like 

 that of a small falcon, with the white rump displayed as a prominent 

 identification mark. When they appeared in the open they were 

 pursued hotly by fork-tailed flycatchers and other related species. 

 The birds taken were breeding (though no nests were observed) and 

 were in somewhat worn plumage. (PI. 9.) 



An adult female shot December 23 had the tip of the bill dull 

 black; base of maxilla light grayish olive; base of mandible mig- 

 nonette green ; cere, gape, skin of lores, and bare skin about eye wax 

 yellow; iris light cadmium; tarsus and toes slightly paler than 

 deep colonial buff; nails black. 



« Syn. Accipitres, ed. 2, pt. 1, Sept. 28, T921, p. 25. 



