Is potty training near?

We've been taking walks around the block when we get home and have dinner early enough. Nicholas and I went out yesterday and stopped to look at all of the trees, flowers, people, cars, the occasional dog and ball lying in someones yard. When we were just around the corner, he started to say poo poo and was grabbing the back of his shorts. I didn't think anything of it, but he kept doing it and did not seem happy. So we turned around and went home and sure enough he pooped in his diaper. Is this a sign that he is ready to start potty training??

On a side note, Nicholas now weighs 30 pounds, 4 ounces.