Redbilled
Redbilled is a seldom-used, single-word variant of the more common hyphenated form red-billed. It functions as an English compound adjective indicating that something has a red bill (beak). In formal writing and standard style guides, the hyphenated red-billed is the preferred form; redbilled may appear only as a nonstandard spelling or in specific databases and informal texts.
The term appears most prominently in the common names of several bird species, where the color of
In practice, the standard spelling in taxonomy and field guides is the hyphenated red-billed, as in red-billed
See also beak coloration in birds, compounding in English, and lists of birds with color-based common names.