202 Tyler, Simultaneous Action. [April 



one can satisfy himself on this point by watching a flock of Ereu- 

 netes pusillus, for example, flying past in bright sunlight. At first, 

 if you are between the sun and the birds, their white underparts 

 shine out as the light strikes under the raised wing; later, in the 

 distance, the birds appear as a group of flickering bright spots, — 

 until the flock turns. Then, in an instant, every bird disappears; 

 each has turned away at the same moment and presents to the eye 

 only the narrow edge of the wings and the smallest diameter of the 

 body, — invisible in the distance. 



One advantage of maintaining a food-shelf is that the birds which 

 visit it, after they have fed, often remain near and afford excellent 

 opportunities for study at close range, while the birds are entirely 

 at ease and wholly unconscious of being observed. At such times 

 they sometimes display traits and habits which under other circum- 

 stances, even after long acquaintance, they will not have shown. 

 For example, in the winter, after a little band of Chickadees have 

 satisfied their hunger at my food-shelf, they often spend half an 

 hour or so in the shrubbery and arbor-vitse trees eight or ten feet 

 from the window. As a rule, they call cheerily to each other; 

 sometimes, however, there comes a sudden hush, — every bird has 

 become silent and perfectly motionless. For minute after minute, 

 by the watch, the birds hold their quiet, and seemingly rigid, atti- 

 tudes. I have timed them thus for eight minutes. It is difficult 

 to find them as they sit as if frozen to the twigs; they are perched 

 here and there, widely separated, some half -hidden in the evergreens, 

 others exposed on bare branches. At last the stiff pose gradually 

 gives way; one bird begins to move his head, — to look about a little 

 from side to side. Every other bird is acting in the same way; 

 now all are hitching slightly on their perches, some of them utter- 

 ing their conversational notes in an undertone; now one or two 

 give a rapid jingling call and hop from their perches; the spell is 

 broken ; the frozen statues are once again living, active, wide-awake 

 Chickadees. 



The point of especial interest here is the identical behavior of the 

 birds, — their prolonged immobility, their silence, their quick pas- 

 sage from death-like stillness to activity. Although, to be sure, 

 the transition occupies several seconds, the birds pass through, it 

 simultaneously (as nearly as the eye can follow their movements) 



