Birds can eat beans but the beans must be cooked first.
Undercooked or dried beans are extremely harmful to birds. Uncooked beans contain hemagglutinin, which is highly toxic to birds. Hemagglutinin can be found in many plants, and uncooked red kidney beans have the highest levels.
Cooked black beans, green beans, lentils, peas and chickpeas are better for birds.
SOME undercooked beans are not harmful to birds though, don’t take unnecessary risks and remember to cook (steam or boil) the beans thoroughly before feeding birds, and likewise, do not add salt, oil, sugar and any seasoning. Different from vegetables, veggies lose some of their nutritional value under some cooking methods.
Remember, beans cannot be used as the main food for birds.