132 NATURAL SELECTION VI 
of my views of the general theory of protective adaptation. 
Yet it is undoubtedly the fact that in the best known cases 
in which the female bird is more conspicuously coloured than 
the male, it is either positively ascertained that the latter 
performs the duties of incubation, or there are good reasons 
for believing such to be the case. The most satisfactory 
example is that of the Gray Phalarope (Phalaropus fulicarius), 
the sexes of which are alike in winter, while in summer the 
female instead of the male takes on a gay and conspicuous 
nuptial plumage; but the male performs the duties of incubation, 
sitting upon the eggs, which are laid upon the bare ground. 
In the dotterell (Eudromias morinellus) the female is 
larger and more brightly coloured than the male ; and here, 
also, it is almost certain that the latter sits upon the eggs. 
The turnices of India also have the female larger and often 
more brightly coloured ; and Mr. Jerdon states, in his Birds 
of India, that the natives report that, during the breeding 
season, the females desert their eggs and associate in flocks, 
while the males are employed in hatching the eggs. In the 
few other cases in which the females are more brightly 
coloured, the habits are not accurately known. The case of 
the ostriches and emeus will occur to many as a difficulty, 
for here the male incubates, but is not less conspicuous than 
the female ; but there are two reasons why the case does not 
apply: the birds are too large to derive any safety from 
concealment ; from enemies which would devour the eggs 
they can defend themselves by force, while to escape from 
their personal foes they trust to speed. 
We find, therefore, that avery large mass of facts relating 
to the sexual coloration and the mode of nidification of birds, 
including some of the most extraordinary anomalies to be 
found in their natural history, can be shown to have an inter- 
dependent relation to each other, on the simple principle of 
the need of greater protection to that parent which performs 
the duties of incubation. Considering the very imperfect 
knowledge we possess of the habits of most extra-European 
birds, the exceptions to the prevalent rule are few, and gene- 
rally occur in isolated species or in small groups ; while several 
apparent exceptions can be shown to be really confirmations 
of the law. 
