the ancestors of the pheasant were arboreal, and hatched their 
young in trees. Otherwise all the wing-quills should develop 
at the same time, and at the same rate. Here, then, is 
another instance of what can be learned of the past history 
of a bird by a careful scrutiny of the nestling. Sometimes 
we shall find our evidence in the wing, sometimes in some 
other organ. The sequence of plumage affords abundant 
evidence of this. But that is another story. 
So much for the “ intensive” study of the wing. A brief 
reference must now be made to the constantly repeated 
statement that nestling birds are “taught” to fly by their 
parents. There is no evidence whatever to support this 
belief : and much that goes to show its improbability. 
Failing more suitable sites, sand-martins will often elect 
to build their nests in the crevices of the masonry of bridges. 
From the mouth of this substitute for a burrow is often a 
sheer drop of many feet to the stream below. When the 
nestlings, fully fledged, leave their nursery for the first time 
they must either “ fly’”’ from the moment they take the first 
plunge from the masonry, or die. Failing to make the appro- 
priate movements of the wings nothing can save them from 
a watery grave. There can be no ‘‘teaching’’ to fly. 
Indeed, death no less certainly awaits every house-martin 
when it plunges into space from the edge of the nest. The 
appropriate wing-movements, necessary to produce flight, in 
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