To my knowledge, only the European starling and house sparrow are not on the protected list. Fifty years ago I heard of a bounty that was placed on Red Winged Black birds for causing destruction in cotton fields.
If birds or mammals are causing crop destruction, the landowner/farmer has to get permission to stop this. I don't think poisoning is on that list in todays culture.
This from the Center for Wildlife Damage Management website: "Toxicants Starlicide is a registered toxicant for blackbirds and starlings in feedlot situations. The active ingredient, 3-chloro-p-toluidine hydrochloride, is incorporated into pelletized bait at a concentration of 0.1% and sold commercially under the trade name Starlicide Complete®. Starlicide Technical® (98% active ingredient), which can be custom-mixed with livestock feed or other bait material, is also available through the USDA-APHIS-Wildlife Services Program. Starlicide Technical® can be used only by or under supervision of Wildlife Services employees.
Starlicide is a slow-acting toxicant; birds usually die 1 to 3 days after feeding. Baiting programs are most successful in winter, especially with snow cover present, when alternate foods are scarce. A successful program generally requires a period of prebaiting with nontoxic bait to accustom the target blackbirds and starlings to feed at specific bait sites inaccessible to livestock in the feedlot. Monitoring to ensure that nontarget birds such as doves, song birds, and barnyard fowl do not feed at bait sites is essential.