OWLS. 169 



When brown owls hoot, their throats swell as 

 big as an hen's egg. I have known an owl of this 

 species live a full year without any water. Perhaps 

 the case may be the same with all birds of prey*. 

 When owls fly, they stretch out their legs behind 

 them, as a balance to their large heavy heads ; for, 

 as most nocturnal birds have large eyes and ears, 

 they must have large heads to contain them. Large 

 eyes, I presume, are necessary to collect every ray 

 of light, and large concave ears to command the 

 smallest degree of sound or noise. 



It will be proper to premise here, that the fifty- fifth, fifty- 

 seventh, fifty-ninth, and sixty-first letters have been published 

 already in the Philosophical Transactions ; but, as nicer observa- 

 tion has furnished several corrections and additions, it is hoped 

 that the republication of them will not j^ive offence; especially 

 as these sheets would be very imperfect without them, and as 

 they will be new to many readers who had no opportunity of 

 seeing them when they made their first appearance. 



The hirundines are a most inoffensive, harmless, 

 entertaining, social and useful tribe of birds ; they 

 touch no fruit in our gardens ; delight, all except 

 one species, in attaching themselves to our houses ; 

 amuse us with their migrations, songs, and marvel- 

 lous agility : and clear our outlets from the annoy- 

 ances of gnats and other troublesome insects. Some 

 districts in the South Seas, near Guiaquil f, are de- 

 solated, it seems, by the infinite swarms of venomous 



* All birds of prey are capable of sustaining the want of food 

 and water for long periods, particularly the latter, but of which 

 they also seem remarkably fond, drinking frequently in a state 

 of nature, and, during summer, washing almost daily. W. J. 



f See ULLOA'S Travels. 



