278 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



dark neutral gray, extending forward irregularly into the brighter 

 color of the tip; bare skin of throat and side of head deep red; an 

 area of marguerite yellow on lower eyelid, concealed when the eye 

 is open ; tarsus and toes coral red ; claws black. 



Another male, from Armila, San Bias, March 2, 1963, had the iris 

 reddish orange; cere, gape, and mandibular rami light blue; rest of 

 bill bright yellow ; bare skin of throat and side of head orange-red ; 

 tarsus and toes bright reddish orange ; claws black. 



A female from the mouth of the Rio Tuquesa, Darien, March 22, 

 1959, otherwise similar, had the tarsus and toes orange red. 



Measurements. — Males (10 from Panama), wing 340-355 (346), 

 tail 229-248 (239), culmen from cere 24.0-26.7 (25.6, average of 8), 

 tarsus 52.0-57.5 (54.1) mm. 



Females (7 from Panama), wing 331-362 (344), tail 227-258 

 (243), culmen from cere 22.9-27.9 (25.5, average of 6), tarsus 53.4- 

 60.0 (56.2) mm. 



Resident. Locally fairly common in forested areas in the tropical 

 zone. Found to 600 meters on Cerro Pirre, at 1000 meters and more 

 rarely to 1500 meters on Cerro Mali, the highest elevations on the 

 isthmus at which it has been reported. Not recorded from the 

 Pacific slope in Code, Herrera, or Los Santos. 



A first acquaintance with this interesting forest species of the 

 falcon family is certain to come through its loud, raucous calls of 

 cao ca cao, ca ca cao, kee yow-w-w, with other variations. The birds 

 frequently range in groups of half a dozen but are found in pairs 

 toward the end of the dry season. At a distance their cawing, croak- 

 ing calls in their harsh, explosive tones sometimes suggest the notes 

 of macaws, but near at hand they are like nothing else heard in 

 the forest. Only in amount of noise produced do they suggest those 

 of the laughing falcon, whose calls have a certain musical intona- 

 tion entirely lacking in the present species. At times when a pair 

 of red-throated caracaras has lingered in the trees near my forest 

 camps their harsh, continued racket has passed the amusing stage to 

 become a bit annoying. 



These birds range through the tree crown, flying rather heavily 

 with quickly flapping wings, which then are set to sail for short 

 distances when they have sufficient momentum. In places remote 

 from settlement, where ammunition is too valuable to use except to 

 kill game, the cacao is often tame and so curious that it may fly down 

 within a few meters to watch any human intruder, always with a 

 steady repetition of its calls. The bird is one that is widely known 

 through its noisy habits, and its notes are the base of several names. 



