194 BIRDS OF THE REPUBLIC OF PANAMA PART 2 



the abdomen thrown forward over the egg. When the egg hatches 

 the young bird remains in the same spot. So safe is this that country- 

 men sometimes believe that egg and young have been secured by some 

 glue applied by the parent! R. E. Johnson (Illustrated London News, 

 March 13, 1937, p. 436) recorded the incubation period in Trinidad as 

 30 days. The young bird remained in position for another 40 days. 

 For the first 3 weeks it was covered constantly by a parent, the two 

 alternating in this care. For the rest of the period one of the adults 

 was with it constantly. When the young bird finally left it was strong 

 in flight. 



Muir (Ibis, 1925, p. 655) described an egg from Trinidad, of the 

 race Nyctibius griseus griseus, as "dull white profusely spotted and 

 streaked with brown with underlying markings of grey, more so at 

 one end." This egg measured 40x25 mm. Sick (Vogelwelt, 1951, 

 p. 42, pi. 14) describes an egg also listed as that of Nyctibius griseus 

 griseus, found in Ilha Grande, Rio de Janeiro, Brazil, as without 

 gloss, white, spotted with chocolate brown and lilac-gray, some of the 

 markings large (3 mm. in diameter), others fine spots. The form as 

 shown in the illustration is elliptical. This egg measured only 36.2 X 

 29.0 mm. Possibly it is of another race. 



The large broad head in this species is supported by lateral expansion 

 of the base of bone. Openings for the eyes are huge, with the mecha- 

 nism of the ears, and of the support for the mandible, expanded below. 

 The bone itself is a series of plates and struts that is strong but light. 

 The transverse width of the open mouth may be 50 mm. The con- 

 siderable lateral expansion of the skull has no relation to the brain, 

 which is tiny compared to the great size of the bird. On one occasion 

 in the course of preparing specimens, I noted that the cranial cavity 

 was identical in size with that of a tiny piculet. Danforth (Auk, 1928, 

 p. 486) gave the dimension of the brain cavity in a male collected in 

 Jamaica, of a race larger than that of Panama, as 12 X 14.5 mm. 



Those who dwell near forested areas from Panama to northern 

 South America will assure the listener that the nocturnal song of this 

 bird is the call of a sloth, a superstition that dates back to the writings 

 of Oviedo. Perhaps this belief is responsible for the lack of a common 

 name, as those who see the bird mistake it for an owl, and usually 

 call it lechuza. Uriitau, current appelation for the species from Brazil 

 to Argentina and Uruguay, from the Guarani language, signifies a 

 ghost or phantom bird. In Trinidad the bird is called poor-me-one. 



As a species the lesser potoo is found in the Greater Antilles in 

 Hispaniola and Jamaica, each with a well-marked race of large size. 



