Okay so that old saying that they will get thirsty enough and just start drinking from it. Intirely not true. My son almost got dehydrated because I kept thinking that. He would drink everything from a sippy cup except milk. So I decided that I just wouldn't give a bottle at all. Well it came back and bit me. He went on strike and didn't drink anything all day from a bottle or sippy. I had to get creative and ended up teaching him how to drink from a straw. But that was after numorous calls to my husband at work and the Dr. He ended up drinking his first milk for the day at 9:00pm.
A few weeks after his 1st birthday he got a really bad sinus infection and he couldn't breath when he tried to drink out of a bottle so he started throwing that on the floor. He basicly gave it up himself. Just remember if your child is as stubborn as mine be careful and make sure that he is still getting his fluids. We came real close to making a trip to the emergency room.