Bindi Irwin has paid tribute to her "guardian angel" dad Steve Irwin 16 years after his death. The legendary wildlife expert died on September 4, 2006 aged 44 following a freak accident with a stingray and his daughter Bindi remembered him on the anniversary of the tragedy in a sweet message declaring he would have been a wonderful grandad to her little girl Grace. She wrote: "Grandpa Crocodile, I know you would've been the most incredible grandfather because you were such an extraordinary dad.