Do surgeons do colonoscopy or sigmoidoscopy?

Both: Surgeons do sigmoidoscopy and those with special training ( colorectal surgeon) do both.

Both: Depends on the experience of the surgeon and their training. Colon and rectal surgeons specialize in disorders of the colon and rectum and have had training in colonoscopy procedures and typically perform both as part of their practice. General surgeons may or may not perform sigmoidoscopy or colonoscopy, depends on their training and specific practice patterns.

Both: We are trained for all manners of endoscopy. Most however don't do colonoscopy and at most do a rigid proctosigmoidoscopy attime of left colon surgery.