FAMILY TROCHILIDAE 247 



throat, or as one wheels the tail, normally closed, may be spread to 

 reveal the deep fork. The call is a low chatter. 



Because of the height at which they fly few specimens are taken by 

 shooting. At Juan Mina on the Rio Chagres I have fired at them at 

 long range, but my only specimen did not fall immediately. When 

 found the following day it had been eaten by ants and so was kept for 

 a skeleton. 



This is the principal species known as the Macud. The birds, cap- 

 tured by the countryman at their nests, are split half way through the 

 body with knife or machete and are flattened and dried in the sun. 

 Flesh and bone, powdered and mixed in perfume, have high repute 

 among the superstitious as a love charm. 



The typical race P. c. cayennensis ranges widely from Chiapas south 

 through Panama to Brazil. Moore (Proc. Biol. Soc. Washington, vol. 

 60, Dec. 31, 1947, p. 143) found that a male from Presidio, Veracruz, 

 the first recorded from Mexico, was larger (wing 126.8 mm), and 

 named it Panyptila cayennensis veraecrucis. 



Family TROCHILIDAE: Hummingbirds, Colibries 



This interesting family of birds, known only in the Americas, is 

 distributed from Alaska to Tierra del Fuego, with the greatest con- 

 centration among its 320 species found in the northern half of South 

 America. In Panama 54 species have been recorded, 1 of them migrant 

 from the north, the others resident on the Isthmus, though some shift 

 about with changes in the seasons. 



The plumage in most has an iridescent metallic sheen, with males 

 usually more highly colored than females. Dimensions vary from a 

 few no larger than a big wasp to others equal in body size to small 

 warblers. All, regardless of bulk, are aggressive, driving fearlessly at 

 birds of any size that pass, in addition to constant bickering with 

 other species of the family. Most feed regularly at flowers, both on 

 nectar and on the small insects found in them. When small flies 

 gather in dancing multitudes in the air, various hummers circle tire- 

 lessly among them seizing them on the wing. 



In nesting season males of some species have dashing displays to 

 attract the females. Others gather in scattered groups in thickets and 

 trees to sing squeaky, chattering songs. Females alone build the nests, 

 incubate the 2 small white eggs, and feed the young. 



Method of flight in this family is peculiar in that the main move- 

 ment comes at the shoulder, with the wing as a whole rotated through 

 an angle of 180° in what has been termed flagging flight, instead of the 



