The site does however claim that he was 3 in 1967 which wouldn't fit in with a 1961 birthdate, it would mean he was born in 1964, just as the date that his father left to attend Harvard of 1965 doesn't fit in.
Obama Sr. leaving when Obama was 1 year old would fit in with either leaving in 62 when Obama was born in 61 or leaving in 65 if Obama was 1 year old in 64.
Should read if he was born in 64.