THE SHAPES OF BIRDS 265 



trees. Mr. Gates adds, " they seldom or never descend 

 to the ground." 



This statement is not strictly true. I have repeatedly 

 seen the fantail, the grey, and the black and orange 

 species on the ground. But the point I desire to em- 

 phasise is that their methods of obtaining food are all 

 very much the same. Were all the species of the same 

 colour and shape, I think few observers would be able 

 to distinguish one species from another, merely by 

 watching their methods of securing food. Their varied 

 nesting habits would, of course, serve to distinguish 

 them. 



Here, then, we have five species of birds, living side 

 by side, under similar conditions and eating the same 

 description of food, obtained by like methods, yet 

 arrayed in totally different plumage and of varying 

 form. 



Passing over the differences in colouration, let us con- 

 fine ourselves to configuration. Why are these birds 

 not all of the same shape? They are related to one 

 another ; all are descendants of a common ancestor, 

 and, as we have seen, their methods of obtaining food 

 are not marked by any considerable differences ; why, 

 then, are they not all of one shape the shape best 

 suited to flycatching birds ? 



I do not think for a moment that it is possible 

 successfully to maintain that the shape of each par- 

 ticular species is so important to it that, were the bird 

 of any other shape, it must perish in the struggle for 

 existence. The paradise flycatcher disproves such an 

 hypothesis. The male and female differ considerably 



