Giant Goatsucker of Brazil. 517 



taken between 1 and 2 o'clock in the afternoon. The sun 

 already strikes the bird a little behind, and its head shews 

 the same tendency to assume a position diametrically oppo- 

 site to the direction of the sun, having turned back about 

 45° towards the original position. The eyes are closed as in 

 the preceding case. 



The fourth figure represents the Nyctibius as photographed 

 between 3 and 4> o'clock in the afternoon. The sun is now 

 striking it more directly from behind. The head has 

 resumed the original direction, but, when compared with 

 the first figure, shews, by its downward pose, that the strong 

 afternoon sunlight is still felt to be unpleasant. The eyes 

 are closed, though perhaps not so much as in the two 

 preceding figures. 



Now let us ask, what are the results of this investigation ? 

 Is the popular notion confirmed or refuted ? The facts are 

 certainly contrary to the popular idea, as might have been 

 expected from numerous analogies among other nocturnal 

 birds and mammals. It is true that in the morning the 

 Nyctibius is still wide awake, and seems to feel no dis- 

 comfort, but rather pleasure, from the early sunlight. It is 

 easy to understand that a moderate amount of light and heat 

 would feel agreeable after the cold and damp of the latter 

 part of the night, especially under an equatorial sky. This 

 is a law to which all the higher vertebrates, both mammals 

 and birds, are subject, not excepting those that are purely 

 nocturnal. A certain degree of activity is to be noticed' 

 in the early morning and late in the afternoon among a 

 large number of nocturnal representatives of the two classes 

 above mentioned. 



The Nacunda {Podager nacunda), a medium-sized Goat- 

 sucker, which is extremely common along the rivers of the 

 Island of Marajo, and is seen in small flocks at certain times 

 of the year flying over the city of Para, can be observed 

 in its majestic aerial evolutions as early as -A o'clock in the 

 afternoon, a fact quite sufficient to surprise a man otherwise 

 familiar with the habits of bird-life. 



In Southern Brazil another very common Goatsucker 

 SBR. VIII. — vol. iv. 2 p 



