Todd-Carriker : Birds of Santa Marta Region, Colombia. 159 



heard when one is in the vicinity of its haunts. It is a shy bird and 

 very difficult to approach, perching high up in the trees and sitting 

 quietly. 



54. Micrastur brachypterus brachypterus (Temminck). 



Micrastur semitorguaius (not Sparvius semitorquatus Vieillot) Salvin and 

 GoDMAN, Ibis, 1880, 177 (Valencia). — Bangs, Proc. Biol. Soc. Washing- 

 ton, XII, 1898, 132 ("Santa Marta"). — Allen, Bull. Am. Mus. Nat. Hist., 

 XIII, 1900, 130 (Bonda). 



Nineteen specimens: Bonda, Neguange, Cincinnati, Mamatoco, Di- 

 bulla, and Fundacion. 



The true explanation of the color-variations so conspicuous in this 

 species would seem to be simply dichromatism. Thus, of nine adults 

 in our collection four are white below, while five are buffy, varying 

 from buffy white to deep buff. Of ten young birds two have the 

 ground-color of the under parts pure white, in two others it is slightly 

 tinged with buffy, and in the remaining six it is decidedly buffy. 

 There is only one specimen (No. 41,813, Mamatoco, April 15) which 

 does not entirely lend itself to this explanation. This is a' young bird 

 which is assuming the adult dress by moult. The throat, breast, and 

 chest are rich buffy, immaculate, while the rest of the under surface is 

 white, in abrupt contrast, barred with dusky black. But perhaps this 

 merely goes to show that the white and buff phases are interchange- 

 able by moult. 



We have not seen Ecuador specimens, which have lately been de- 

 scribed as a distinct race (Swann, Synoptical List of the Accipitres. 

 II, 1919, 15), but Colombian birds are precisely like those from Bolivia. 



This Micrastur is not an uncommon bird in the Tropical Zone low- 

 lands, apparently on all sides of the mountains. It was secured by 

 Simons at Valencia, and by Messrs. Smith and Brown in the neighbor- 

 hood of Santa Marta, while the writer has traced it from Dibulla on 

 the north coast to Fundacion on the south. It is found only in the 

 forest or open woodland, and keeps rather low down, often in the 

 tangled thickets. 



55. Falco peregrinus anatum Bonaparte. 

 One specimen: Bonda. 



The only record for the Duck Hawk in this region is based on a 

 single specimen in immature dress secured at Bonda, October 20, 

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