Water Fowl 
On the other hand, the commonest species 
of water birds are much more equally distrib- 
uted among all the orders, and the variety of 
types therein is very extreme. This affords a 
most interesting diversity. About nine-tenths 
of all the land birds which the average student 
will find are in the song group; which are 
classified, to be sure, into about twenty fam- 
ilies ; yet the general type of all of them is so 
uniform that the observer would hardly consider 
it incongruous if they had been arranged in 
two instead of twenty families. Thrushes, 
finches, tanagers, waxwings, and blackbirds, 
only differ in subordinate details ; and certain- 
ly warblers, vireos, and fiycatchers are com- 
paratively uniform in general figure. 
But notice the remarkable gradation, not in 
size only, but especially in the fundamental 
structural form of the various groups of water 
fowl, as represented by the sandpiper, oyster- 
catcher, woodcock, phalarope, avocet, rail, 
curlew, heron, pelican, flamingo, swan, duck, 
penguin, cormorant, snake-bird, loon, gull, guil- 
lemot, puffin, grebe, petrel, albatross—a variety 
of types consistent with their extreme diversity 
of life, as wading, swimming, diving, and aérial 
water fowl. When all the varieties of figure 
53 
