nuthatch

noun1

1. •
   Any of various small passerine birds from the genus Sitta, found throughout the northern hemisphere and noted for their unusual proclivity for climbing down trees head first.

   • The bird was in very faded plumage with only a slight rusty wash to the underparts, and had I not heard the call, I might have mistaken it for a Pygmy Nuthatch. — 1996