Run a little peroxide over that (not any other disinfectant, ONLY hydrogen peroxide, other disinfectants could leave a toxic residue), then run under cold water, dry with sterile gauze ASAP and then call the vet. If you don't have hydrogen peroxide on hand, then just run the foot under cold water and dab with sterile gauze to at least stop the bleeding. Infection can set in so quickly, it is important to treat the wound as best as you can at home then get the bird into a vet who can examine the wound, further treat it and give precautionary antibiotics if he/she feels it is necessary.