The slaty gray shade in the plumage appears to be a sign of the breeding season, as some of the winter specimens are black with a greenish gloss on the upper surface.
Bill long, compressed, and curved downward, its tip blunt and rounded; on each side of culmen a longitudinal groove in the basal portion of which the nostril is pierced.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "rump and upper tail" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.