VISION. 23 



to avoid trees and other obstacles*. It is probable, 

 indeed, that the proverbial stupidity of the bird arises 

 from this weakness of sight. Like the owl, indeed, 

 its motions are much more agile and lively at night- 

 fall and dawn than at any other time ; and so strong 

 is this propensity to action at the rise or descent of 

 the sun, that woodcocks when kept in a room are 

 observed to flutter about regularly every morning and 

 evening, while during the day they only trip on the 

 floor without attempting to fly. 



The stone-curlew (CEdicnemus crepitans, TEM- 

 MINCK) differs from the woodcock particularly in 

 this, that though its eyes are similarly prominent, 

 yet, if we may believe M. Montbeillard, its sight is 

 very acute in the daytime, though he admits it can 

 see best in the twilight. The prominence of its eyes 

 enables it to see behind as well as before, and it is 

 with difficulty therefore that it can be approached f. 

 Paley justly remarks that *' what is gained by the 

 largeness or prominence of the globe of the eye is 

 width in the field of vision.'* 



With respect to owls, as well as most night-prowling 

 animals, the eye is unquestionably very sensible. Of 

 the barred owl (Strix nebulosa, GMELIN) Audubori 

 says, its " power of sight during the day seems to be 

 rather of an equivocal character, as I once saw one 

 alight on the back of a cow, which it left so suddenly 

 afterwards, when the cow moved, as to prove to me 

 that it had mistaken the object on which it had 

 perched for something else. At other times I have 

 observed that the approach of the grey squirrel inti- 

 midated them, if one of these animals accidentally 

 jumped on a branch close to them, although the 

 owl destroys a number of them during twilight}." 



* Ornith. Diet. p. 562, 2d edit. 



f Oiseaux, Art. Le grand Pluvier. 



J Ornilh. Biography, p. 244. 



