If grackles are depredating, you can hunt them.
Yellow-headed, red-winged, rusty, or Brewer's blackbirds and all grackles, cowbirds (does not include cattle egret), crows, or magpies may be controlled without a federal or state depredation permit when found committing or about to commit depredations on ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in numbers and in a manner that constitutes a health hazard or other nuisance.