234 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 150 



bird at such times shows two rounded light patches at the center of 

 each of the wings. 



The main nesting season appears to begin in February and seems 

 to be in full course in March, as adult birds then were found in pairs. 

 I saw them carrying sticks for building and have noted nests under 

 construction in the edge of mangrove swamps, usually at an eleva- 

 tion of about 12 meters, but I was not successful in obtaining eggs. 

 Paired birds are especially noisy at this time, and so their high- 

 pitched calls — repetitions of single notes — are heard regularly, a 

 pleasing sound during long afternoons in camp when I was occupied 

 with notes and specimens. 



Usually they were tame, since, as stated above, they have few 

 human intruders in their swampy haunts. On occasion in a cayuco 

 I have passed within 10 meters of birds that were watching for food, 

 without disturbing them. They spend much time on low perches and 

 often have not been at all alarmed when I stopped nearby for a few 

 minutes to share their cool shade. At low tide they come out to rest 

 on rocks or open beaches and mud flats. Immature birds frequently 

 were curious, particularly when I was calling to attract small birds. 

 While the principal food as noted is crabs, I have had some complaint 

 from persons living at the borders of swamps that these hawks 

 sometimes took small chicks. Mangrove warblers and other swamp 

 inhabiting species, however, were not at all nervous when these hawks 

 were nearby, indicating that they are not regularly predatory on small 

 birds. 



Individual variation in depth of color and in extent and kind of 

 lighter markings is so great that there has been uncertainty as to the 

 population groups that may be recognized. From examination of over 

 200 specimens I find only two that appear valid, aside from the bird 

 of the island of Cuba which it appears appropriate to treat as a 

 separate species, ButeogaUus gundlachii. 



The nominate race, B. a. anthracinus, marked by larger size, ranges 

 from southern Arizona, southern New Mexico, and southern Texas 

 south through tropical Mexico (except the coast of Chiapas) and 

 Central America to Panama (except for the lowlands along the 

 Pacific coast) , and across northern Colombia and northern Venezuela 

 to northwestern British Guiana, including also the islands of St. 

 Vincent and Trinidad. A decidedly smaller form B. a. hang si, is 

 found along the Pacific in the mangrove swamps and adjacent low- 

 lands from northwestern Peru to Chiapas. Both races occur in 

 Panama. Measurements that serve to separate them are given in the 

 accounts of the subspecies that follow. 



