HINTS TO ORNITHOLOGISTS. 295 
birds partake of a vegetable and an insect diet, so 
are these bristles more or less developed. But the 
fallacy of this theory is manifest in the ordinary 
habits of the barn-door fowl, the wigeon, and many 
other birds. During the summer months, the barn- 
door fowl, whilst cropping the grass and herbs, will 
capture, with the utmost facility and avidity, every 
insect, great or small, or soft or hard, which is un- 
fortunate enough to be within its reach. The diet 
of the wigeon is grass. Still, neither the wigeon, 
nor the barn-door fowl, have bristles at the beak. 
The claws of rapacious birds are pronounced to 
be “retractile.” If they are so, then the knowledge 
of internal anatomy would force us to pronounce 
the claws of other tribes of birds, such as the 
robins, the doves, the barn-door fowls, and a thou- 
sand others, to be retractile. 
The soldier must spend many a day amid the 
roar of hostile cannon, before he becomes qualified 
to command an army; the carpenter ought to 
work for years in the dock-yard, ere he attempts to 
build a line-of-battle ship; and the schoolmaster 
has to pore over many a scientific volume, in order 
to prepare himself to teach the mathematics. 
But, somehow or other, it happens, now-a-days, 
that practical knowledge does not seem to be con- 
sidered essentially necessary for those who under- 
take to write on certain parts of Natural History. 
Thus, some there are who will offer their history 
of birds to the public, although it can be ascer- 
tained that they have never been in the country 
which those birds inhabit. Others again, not 
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