Can Your Pediatrician Call Cps on You for Having a Small Baby??

Yes he can call CPS. You might want to consider that since you didn't like what he had to say you might have come across as defensive and unwilling to cooperate. That might have made him nervous on whether or not you were telling the truth about what you feed her. He's probably not against breast feeding, just more concerned with whether or not your body is producing enough for her to grow on. I think that you were wise to get another doctor if you didn't feel that you and him were on the same page. You might just want to consider that it's on his shoulders if he doesn't call and there were really something wrong. If she's healthy and fine than CPS will really have not further reason to investigate. It's about protecting the children.

You need a new pediatrician. ANY ped who is against breastfeeding isn't worth his salt- or else doesn't read medical studies.
Plus he should consider your family! My son was 18 lbs at 1 year, and my husband and I are lanky people.

What was the stated reason CPS showed up? You don't actually have to tell me, it's just that they don't make random stops and they should have told you why they were there.

Also, you may want to talk to a lawyer about CPS.

Get rid of that pediatrician. He's a nutcase.

I am no expert but I have worked in a hospital and know that the doctors do have the power to call CPS if they feel like a situation warrants it.
I think it is really sad and shocking that the doctor just decided to call CPS like that. Did CPS say that they were there because the DR. wanted you to start your baby on formula? Did he talk to you about this before?
On the medical side the doctor is responsible for the health of your baby and I can understand a Dr doing this if the baby was malnourished and you did not want to follow his advice.
But from what you write, your baby is healthy, active and happy. She definitely sounds like she's getting plenty of nutrition. I think too many people rely on charts and percentages. You are her mom and you know your baby better than anyone.
Have you thought about supplementing breastfeeding with formula?
Don't stress too much. You sound like you are taking excellent care of her. I would, however, change doctors if I were you.
But i would also talk to the doctor and ask him why he made this decision.

Get a new pediatrician! She is not underweight in the least! It sounds like you are doing a great job of nourishing your baby!