18.01.2013 Views

The Descent of Man

The Descent of Man

The Descent of Man

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

the natural selection <strong>of</strong> so-called spontaneous<br />

variations <strong>of</strong> instinct, might readily be led to<br />

modify their manner <strong>of</strong> nesting.<br />

This way <strong>of</strong> viewing the relation, as far as it<br />

holds good, between the bright colours <strong>of</strong> female<br />

birds and their manner <strong>of</strong> nesting, receives<br />

some support from certain cases occurring<br />

in the Sahara Desert. Here, as in most other<br />

deserts, various birds, and many other animals,<br />

have had their colours adapted in a wonderful<br />

manner to the tints <strong>of</strong> the surrounding surface.<br />

Nevertheless there are, as I am informed by the<br />

Rev. Mr. Tristram, some curious exceptions to<br />

the rule; thus the male <strong>of</strong> the Monticola cyanea<br />

is conspicuous from his bright blue colour, and<br />

the female almost equally conspicuous from<br />

her mottled brown and white plumage; both<br />

sexes <strong>of</strong> two species <strong>of</strong> Dromolaea are <strong>of</strong> a lustrous<br />

black; so that these three species are far<br />

from receiving protection from their colours,<br />

yet they are able to survive, for they have ac-

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!