favor a reminder of their normal enemies

Thirty
step down in the winter namely chilly, wasteland , field, glacier , desert, quagmire are covered at thick snow , the snow world .
black ravens flew . They are in teams , large , white world fell .
contrast , dazzling eye-catching .
like a reminder of their natural enemies , the exact situation of its subsistence .
they grant themselves apt be the most vulnerable Target of the onset .
I studied Darwin 's theory of evolution , that animals have a elementary alive conditions can alteration their color tone and the instinct to defend themselves hidden , so that predators can not deadlock or simply ascertain themselves. while too In mandate to masquerade themselves near to their pillage , capture prey .
these crows do then ? the inverse. They come year after year, beginning in the snow season , while the snow melts away .
them annual after annual In the dark .
them year after year, accompanied with sleet .
I noticed that beasts not merely in the dark in the dazzling white of the snow striking . and in loess, virtually whichever natural surroundings, green , etc. The most lightly Adversary namely . Some human say there are white crows in the globe . But thousands of years , the vast majority remains a dark crow .
crow that puzzle me, I am puzzled Darwin .
Who can annotate the hidden of the crow ? Nature The secret ?