THE SHAPES OF BIRDS 263 
as soon as we learn all the habits of the creature in 
question we shall see how perfectly its colour is adapted 
to its mode of life. This may be so. Nevertheless this 
kind of argument is not scientific. It tends to stifle 
inquiry, which is the true spirit of science. 
The fact is that natural selection is a horse ridden to 
death. It is indisputably a most important factor in 
organic evolution, but are we justified in regarding it as 
the only factor? It is unable, I think, to explain many 
natural phenomena. One of these is the varying shapes 
of nearly allied animals. 
Certain it is that the general form of a class of 
organisms is determined by natural selection, but are 
the thousand and one shapes seen among closely related 
creatures all to be explained by saying that were these 
of any other form they would perish in the struggle for 
existence? 
Birds afford a striking example of the many shapes 
which may be assumed by creatures of very similar 
habits. I recently visited the Nilgiris, and spent many 
hours in a wood which might appropriately be called 
“The Flycatchers’ Wood.” No fewer than five species 
of that family are common in the wood of which the 
area is less than 5000 square yards. All these species 
have very similar habits. 
To enumerate them. There is first the white-browed 
fantail flycatcher (RAipidura albtfrontata), a bird too 
well known to need detailed description. It will suffice 
that its chief characteristic is the tail, which it continu- 
ally spreads out into a fan. This appendage is about 
three and a half inches long, that is to say, equal in 
