VISION. 237 



Like the owl, indeed, its motions are much more 

 agile and lively at nightfall and dawn than at any 

 other time ; and so strong is this propensity to ac- 

 tion at the rise or descent of the sun, that wood- 

 cocks 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 (OEdicnemus 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 ap- 

 proached. 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 (Slrix nebulosa, GME- 

 LIN), Audubon 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 afterward, 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 gray squirrel intimidated them, if one of 

 these animals accidentally jumped on a branch close 

 to them, although the owl destroys a number of 

 them during twilight." M. Vaillant mentions a 

 similar circumstance which he more than once ob- 

 served in different species of owls, if they chanced 

 to be roused from their lurking-places by day, when, 

 instead of pursuing small birds, which are their nat- 

 ural prey, they fled from them in fear. 



Wilson says of the snowy owl (Stryx nyctea), that 



