LESSER WHITETHROAT 
Let me describe the behaviour of certain species when 
the sexual instinct is uppermost. Savi’s Warbler, with out- 
spread wings and tail, tumbles rather than climbs down the 
stem of the Aruwndo phragmites, and, upon reaching the mass 
of dead reeds at the bottom, follows, while slowly flapping its 
wings, in the wake of the female. The Rook (Corvus frugil- 
egus), lying upon the ground, expands its wings and flaps them 
slowly in a helpless manner. The Cormorant (Phalacrocoraxz 
graculus), while lying upon a rock, behaves similarly to the 
Rook ; extending its wings, it flaps them slowly, at the same 
time raising its outspread tail almost at right angles to its 
body. Numerous instances could be given showing that it is 
only necessary for circumstances of a sufficiently stimulating 
nature to arise in order that the corresponding activities 
should be produced, and in all such cases it is impossible not 
to be impressed with the very helpless appearance of the bird; 
it would, in fact, in some instances, be as easy, if not more 
so, to imagine the whole behaviour an act of simulation, 
than many of the cases which are unhesitatingly referred to 
that cause. 
Now to all of this an objection may be raised on the ground 
that the one link necessary to complete the chain of evidence 
is missing—namely, that in no single instance is the same 
species mentioned as behaving in a similar manner, not only 
at the period in which the parental instinct is dominant, but 
also at other periods of excitement ; and, while fully admitting 
the validity of such an objection, I shall reply to it as follows: 
Firstly, that if it could be shown that all the species, or 
even a considerable proportion of them, that behaved in the 
manner referred to when the nest was approached, behaved 
in the same way at other periods of excitement, if, for 
instance, the Avocet flapped its wings in a similarly helpless 
manner at the period of sexual activity, it would constitute 
proof, and, moreover, proof of a most conclusive kind, that the 
behaviour per se had no special part to fulfil. Secondly, 
that we are not wholly at a loss for the evidence that is 
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