The adult weighs 350 -- 475 g ( 12.3 -- 16.8 oz ) .
The chicks can weigh considerably more , at up to 600 grams ( 21 oz ) , when their parents feed them a good deal of fruit before they fly .
The adult weighs 350 -- 475 g ( 12.3 -- 16.8 oz ) but the chicks can weigh considerably more , at up to 600 grams ( 21 oz ) , when their parents feed them a good deal of fruit before they fly .