White-breasted Nuthatch (Sitta carolinensis)

This largest of the North American nuthatches exhibits some interesting geographic variation. Birds here on the Pacific Slope ("S. c. aculeata") have a thinner more tapered bill, a grayish-brown wash on their underparts and higher pitched and more drawn out vocalizations. In 2013 the AOS considered a proposal to split the White-breasted Nuthatch into two, three or four species, but rejected it pending further research.