Puffinus is a genus of seabirds in the order Procellariiformes. It comprises about 20 small to medium-sized shearwaters. There are two other shearwater genera: Calonectris, which comprises three large shearwaters, and Procellaria with another four large species. The latter are usually named as petrels, although they are thought to be more closely related to the shearwaters than to the other petrels. Despite the resemblance in the name, the puffins are auks, and completely unrelated to the shear… (More on Puffinus)