Hello, Jon. There is no good poison. Anything you use will also endanger other animals including your pets and the birds you enjoy watching and any native predators that might encounter the poisoned rats.

Trapping is the only way I would recommend. A different time-honored direct approach would be having them shot by someone who understands rat behavior and is skilled in safe use of weapons. Either way, removal of all food sources followed by destruction and thorough clean-up of nesting places used by the rats once they have been killed is necessary. Wear a good face mask to prevent inhalation of their dropping fragments.

Continued care in feed storage will be necessary, and we find metal baffles can help prevent the rats from scaling feeder posts. You may like to try trays or baffles designed to catch scattered feed before it hits the ground to be helpful as well.

Good luck.