LECTURES. 27 
fortably to hang her legs. Further observations shewed that the 
flamigo does not hang her legs but sits with them doubled beneath her, 
and the theory held now is that the position of the nest is to allow 
for inundations. 
Now all the theories of which I wish to speak to-day are concerned 
with the life-history of birds and will principally have to do with 
colouring and the so-called instincts. 
With regard to colour, the most obvious thing when one is 
“collecting facts” is the difference in colour between cock and hen 
birds of the same species. I have here a cock and a hen bullfinch, 
and you will see that the colours of the cock are much brighter than 
those of the hen. Now bright colouring appears always to accompany 
strong vitality, so the difficulty is not to account for the bright 
colours of the cock, but for the duller tints of the hen. For an 
explanation we must look to the difference in their manner of life. 
The greatest difference is obviously that the hen sits on the eggs. 
Should an enemy approach and see her she can only save herself by 
deserting her nestlings, and every sitting hen would, if she were 
brightly coloured, be a sure mark for such an enemy. The mother 
being killed, the young who, probably would have resembled her in 
their bright plumage, die. On the other hand a hen whose plumage 
was not so bright, would not only run a better chance of escaping 
notice herself, but would have her life spared to bring up her nestlings, 
who would, of course, tend to resemble her. This happening 
through many generatians would always preserve alive the more 
sober-coloured hens. 
But here I have a kingfisher and she appears to upset our theory, 
for, though not exactly like the cock, she too is brightly coloured. 
But if we follow her to the nest we find she has no need for protective 
colouring, since she lays her eggs on a few fish bones in a hole in a 
bank and cannot be seen when she is sitting. The same applies to 
parrots who lay their eggs in holes in trees. 
Again, at one time it seemed as if the theory was flatly contradicted — 
by the dotterel and other wading-birds as the cock is not so bright as © 
the hen, till it was found that in this case it was the cock and not the 
hen who hatches the eggs. So that instead of contradicting the 
theory of protective colouring this case actually lends support to it. © 
I am afraid that I may have given the impression that the brighter 
colouring was the original one for both sexes and that the female has — 
gradually become duller. Now we know that this is not so, but that | 
the hen, for purposes of protection, has retained the more sober tints, J 
