(noun) The upper part of a bird's body, including the crown, nape, back, wings and rump. The term upperparts is most often used when all of a bird's upper body has similar colors or markings, such as the olive-brown upperparts of the Swainson's thrush or the dark iridescent upperparts of the northern lapwing. The term is also used to form a general impression of a bird's color before describing particular markings or differences that can be used for identification. Depending on the species, upperparts may or may not be the same overall color as the underparts.
When observing upperparts to properly identify a bird, note the overall color "base" of the upperparts. Then look for specific markings that contrast with that base, such as wing bars, back steaks or rump color patches that are distinctive and can be used to distinguish individual bird species.
Photo – Tree Swallow © Putneypics