Comparative Energy in Birds. 



THE members of the feathered tribe, especially small 

 birds, appear to be the most restless of all animals 

 a circumstance which might lead one to conclude 

 that animals are restless in proportion to their diminutive 

 size, were this not in opposition to many other facts. 



The bee, for example, is equally noted for industry and 

 bustling activity with the ant, which is not one-fourth of 

 its size; nay, the Large Wood Ant (Formica rufa) is 

 greatly more active than the very small Black Ant (Ponera 

 contracta). 



The Gnat (Culex) again, a comparatively small insect, 

 seems to repose during the greater part of its existence, 

 remaining fixed in one spot for whole days together, and 

 only moving about for an hour or two in the evening; 

 while there may be observed on the same wall a still 

 smaller insect (Neiedes elegans), seldom moving quicker 

 than the minute-hand of a clock, the motion of which, by 

 interrupted jerks, much resembles that of the insect. 



There cannot, however, be a doubt that the wren and 

 the torn-tit are more active and restless than the bustard, 

 the ostrich, or even than the eagle ; and the activity, more- 

 over, of such small birds is not, like that of the gnat, 

 confined to an hour or two, but continues almost uninter- 

 ruptedly during sunlight, sleep being, it would appear, 

 less necessary than it is to larger animals to restore vigour 

 after exertions so long continued. 



Motion of some kind indeed seems as indispensable 

 to life as food and air ; and even the motions of animals, 

 which may be primarily accounted for by referring to 

 their exertions to procure subsistence, and shelter, and the 

 like, must always, in a secondary point of view, give them 

 beneficial exercise. 



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