262 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



who hears it for the first time without knowing its author. Some 

 complain of its loudness but to me it has always been one of the 

 more pleasing among the stranger tropical sounds. Near at hand 

 paired birds utter lower cackling or chuckling calls that often are 

 quite amusing to the human ear. 



Snakes form the principal food of this species, and in their capture 

 they are most adept. I recall particularly a pair near our little house 

 above Concepcion, in western Chiriqui, that once or twice daily flew 

 past with the limp form of a snake dangling from the feet. One 

 came regularly with its prey into the dead top of a tree on the slope 

 immediately below us, where it called until another, that I believed 

 to be a grown young one, came scrambling up to seize the food 

 and carry it down into the leafy cover below. The parent then usually 

 stood erect with flaring crest, while it called vociferously for several 

 minutes. Often one or both carrying prey flew past uttering guttural, 

 chattering notes that we found entertaining through their resemblance 

 to low-voiced human laughter. On several occasions I saw a chi- 

 mango hawk following as the laughing falcon passed with its dangling 

 prey, and once one came tailed by a group of half a dozen parakeets, 

 all chattering excitedly. These sights were of daily occurrence, but in 

 over two weeks during which I covered miles of the surrounding ter- 

 rain, I myself did not see a single serpent. In the stomach of one that 

 I collected near Alanje, Chiriqui I found the end of the tail of a 

 coral snake that Dr. Doris Cochran identified as Erythrolamprus 

 aesculapii. 



Those who have seen this hawk hunting have told me in detail of 

 how it alights on the ground and spreads one wing whose stiff feathers 

 fend off the strikes of an aggressive snake until the falcon can seize 

 it in one foot near the head and so hold it until it is killed. 



Though this falcon is one of wide distribution, there is little in- 

 formation as to its nesting habits. In southeastern Sonora W. J. 

 Sheffler found it using cavities in cliffs and from one nest collected 

 a young bird several days old. This was covered with light brownish- 

 buff down, paler on the chin and throat, and darker on the upper 

 surface, with a "black facial mask and collar around the nape" like 

 the similar markings of the adult plumage (Sheffler and van Rossem, 

 Auk, 1944, pp. 141-142). The first authentic tgg, sent to Col. L. R. 

 Wolfe (Ool. Rec, vol. 18, 1938, p. 77) from Horqueta, Paraguay, 

 was "clear white, fairly well marked around the large end with flakes 

 and splashes of rich reddish-chestnut and a few flecks of light red 

 scattered over the remainder. Size 56.5x45.6 mm." Later, in 

 Tamaulipas, Wolfe (Condor, 1954, p. 161) flushed a laughing falcon 



