172 
SEXUAL SELECTION : BIRDS. 
n r 
This way of viewing the relation, as far as it 
good, between the bright colours of female birds ^ 
their manner of nesting, receives some support ^ 
certain analogous cases occurring in the Sahara 
Here, as in most other deserts, various birds, and & „ 
other animals, have had their colours adapted in a ^ 
derful maimer to the tints of the surrounding sU ‘i t , v , 
Nevertheless there are, as I am informed by the hh 
Mr. Tristram, some curious exceptions to the rule! ’ ; 
the male ol the Monticola cyanea is conspicuous ^ 
his bright blue colour, and the female almost 
conspicuous from her mottled brown and white pi ot,I %- 
r i ; 1> t\ i p _ v 
(it/ 
, "• CUO HU 11U1U »- sI ]|" 
protection from their colours, yet they are ablet^ 
vive, for they have acquired the habit, when in 
both sexes of tuo species of Dromolsea are of a 
black ; so that these three birds are far from r< ;CCl ' 
' j — x — — '* V J 
of taking refuge in holes or crevices in the rocks* 
With respect to the above-specified groups of ^ 
in which the females are conspicuously coloured . 
build concealed nests, it is not necessary to 
that each separate species had its nidifying ft 
specially modified ; but only that the early prOg e,i j 
of each group were gradually led to build d 0& el j,,. 
concealed nests; and afterwards transmitted 
stinct, together with their bright colours, to their 11 [,, 
fied descendants. This conclusion, as far as it 
trusted, is interesting, namely, that sexual 
together with equal or nearly equal inheritance b' . jjjr 
sexes, have indirectly determined the manner °f ,l) 
cation of whole groups of birds. ^ 
Even in the groups in which, according to M 1 .' ^ 
lace, the females from being protected during 
tion, have not had their bright colours : i 
through natural selection, the males often difl' er ^./ 
slight, and occasionally in a considerable degi' ee > 
