The Mine Bird
The mine bird, Serinus canaria mei, is a close relative to the domestic canary, and is estimated to split off from his cousin less than two hundred years ago. Nowadays, it is not uncommon to come across them in abandoned mines, and sometimes even natural caves.
Descendants of escaped canaries that the miners would take with them, they had to adapt rapidly to survive in their harsh new environment, and this has affected some of their phenological traits in a shocking fashion.
Their feathers have turned completely white, their brightness no longer able to serve as an indicator of fitness in the dark mines. Even flight has become almost useless in the narrow shafts, and with an almost total absence of predators. Mine birds also have significantly smaller bodies than regular canaries, which is probably due to the lack of food, and the constantly warm air which makes thermo-regulation much easier than in a changing environment. Their song, having become their only means of communication, has evolved into astonishingly complex arrangements, and recent studies suggest that it may have a much more varied role than in domestic canaries, where it serves mainly as a mating tool.
How many of these changes are purely phenetic, and how much are of genetic origin, remains to be determined, and scientists are in the process of analyzing the birds' genome and comparing it to that of household canaries. What we do know, however, is that mine birds that are raised in a lab with sufficient food and light are bigger and brighter than those found in the wild.