The Snow Goose occurs in different plumage colorations, known as morphs "Blue Goose" or forms. Overall, the most common form has a snow-white body plumage. However, there are many Snow Geese with dark gray-bluish bodies "Blue Goose". Ornithologists once believed these birds belonged to a separate species, called the "Blue Goose". These birds are now known as the dark or blue morph of the Snow Goose. The white and blue forms readily breed together, and the goslings from a single clutch can be either white or blue — sort of the way humans have brown or blue eyes. In an interesting twist, the Snow Goose retains the former "Blue Goose's" scientific name caerulescens … which explains why this often-all-white bird is labeled otherwise in its species name.