Because it was formerly supposed to head them in their migrations.
Because she may draw away the dog from her helpless covey. - G. White.
Because the two species require very different kinds of cover, and will never interfere. - Sir W. Jardine.
Because they are supported in the centre by bone.
Because madder, a plant yielding a red colour, has been mixed with their food. The nature of the food, generally, also exercises a considerable influence over the colour of their bones.