Grzywacz (Polish) comes from Polish grzywa, from Proto-Slavic griva, from Proto-Balto-Slavic grī́ˀwāˀ, from Proto-Indo-European gʷriHwéh₂, from Proto-Indo-European gʷerh₃- — to swallow, devour, eat.
Grzywacz (Polish): common wood pigeon