Thanks Phil.
Well, last year was the first time I ever saw him, so my age guesses are based on the change I see from then till now. He was too big body wise last year to be a two year old. The gain in mass and body this year makes me think he was three last year and is four this year. If you look at the difference in mass at the bases, its more like what I would expect from 3 to 4 rather than 4 to 5.
What's your thoughts? Does my reasoning seem right?