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birds ; and as it holds nearly the same place among those birds which feed over 
fresh waters upon the wing, as the Auks and Puffins do among those that swim 
and dive, so there is no small resemblance in some parts of the economy. It 
builds in holes of the banks, which holes it excavates for itself. The foot is, in¬ 
deed, a very efficient digging foot, much better than if the tarsus were larger, and 
the toes more produced and free. The eggs are, however, more numerous than 
those of the sea-birds, which the Kingfisher resembles in its breeding places and 
some other of its habits. They vary from four to eight, usually of a pure white 
colour; and as the birds do not walk on the sludgy surfaces the eggs are not 
soiled by their feet, as is the case with those of many lake and river birds. It is 
said that the Kingfishers are very prone to take possession of the holes of the small 
aquatic mammalia and trim them for nesting places ; and some allege that these 
avenge the ejectment by eating the eggs of the birds. This last is not, however, 
very practicable, as the eggs are seldom, if ever, without one of the birds upon 
them ; and if the birds are able to take possession, they are, of course, able to keep 
it. It is true that the number of birds that are seen bears but a small proportion 
to that of the eggs ; and we know that, in most cases, the numbers of the eggs 
of birds bear a proportion to the enemies or other casualties to which they are 
subject. But we have no certain knowledge of the enemies of the Kingfishers, 
or of the casualties that may destroy them, either in the young or the adult state. 
It has been said that the eggs are frequently addled or the unfledged young 
drowned, by the floods of the streams in the banks of which the nests are placed ; 
but the time when these birds breed is that at which floods are the least frequent. 
The probability is that the cold of winter, and the impossibility of finding food when 
the streams are sealed up by the frosts of that season, are the real causes of the 
comparatively limited numbers of these birds in the colder latitudes. This is, in 
so far, rendered probable by the fact that, even in those places where they are 
most likely to be found, Kingfishers are less frequently seen in the summer than 
in the winter. In summer they ascend the streams, near their sources, especially 
if these are in rich and wooded plains, because at this period and in such situa¬ 
tions the smaller fishes are usually numerous ; but toward the close of the season 
the small fishes descend, and when winter fairly sets in, the birds are driven to the 
broad waters, where they are not only obliged to be more on the wing for their 
food, but are also more easily seen, from the leaves having fallen. 
It is probable also that, notwithstanding the compactness of their plumage, 
the Kingfishers are more susceptible to the weather than almost any other of our 
resident birds. The fact of the single species in Europe, and the great number of 
species (as many as between sixty and seventy, leaving out the less aquatic ones, 
which make eight to ten more) that are found in tropical countries, would go far to 
establish this supposition. But there is a physiological argument which is at once 
more conclusive and more important. In all cases in nature there is an adaptation 
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