VERSATILITY OF SPARROW 7 



call them in the ease of persons, are not nearly so 

 familiar, and have not been jvorked out fully even 

 in many very well-known birds. Such are pecu- 

 liarities in gait, flight, and other actions ; attitudes 

 under emotion, positions assumed in repose, etc. 

 Often these have no apparent connection with any 

 necessity, and they are practically invariable for 

 the species and often for the group, and not alter- 

 able by circumstances. 



To take a concrete instance ; the common Spar- 

 row, as every one knows, eats seed, for the cracking 

 of which its bill is specially adapted ; it perches 

 in trees, and has feet adapted for grasping twigs ; 

 it also builds its nest in trees, and associates in 

 pairs and flocks. These are its major habits, and 

 every one knows they are subject to modification ; 

 it eats many things besides seed, especially remnants 

 of man's food ; it builds under eaves as well as 

 among boughs, and will sleep in its nest or in a 

 crevice of a wall, as well as on a twig, in spite of 

 its grasping feet. In spite of its short wings, it 

 chases insects in the air, and hovers and drops 

 on them in long grass like a miniature Kestrel. 



In other words, its major activities are, though to 

 some extent correlated with its structure, highly 

 variable, and this, no doubt, is one great reason 

 for its success as a species. If actively interfered 

 with by man it can vary still more ; a hand-reared 

 Sparrow has been known to acquire a Linnet's 

 or Canary's song. 



In some points, however, the Sparrow is invari- 



