Blue-winged kookaburra highly aggressive in the first week of life, and the youngest chick is often killed by the older chicks during this period. Once fledged, juvenile birds need to be taught how to hunt by their parents for a further 6–10 weeks before they can properly fend for themselves. The red goshawk and rufous owl prey upon the blue-winged kookaburra. Adult birds are also slow flyers and vulnerable to being hit by cars on country roads. Nests are susceptible to raids by Olive Pythons, quolls and goannas. Blue-winged kookaburra The blue-winged kookaburra ("Dacelo leachii") is a large species of kingfisher native
Largest organisms . "Pelagornis sandersi" is thought to have had an even larger wingspan of about , but is only about , half the mass of the former. The following is a list of the heaviest living bird species based on maximum reported or reliable mass, but average weight is also given for comparison. These species are almost all flightless, which allows for these particular birds to have denser bones and heavier bodies. Flightless birds comprise less than 2% of all living bird species. The largest living amphibian is the Chinese giant salamander ("Andrias davidianus"). The maximum size of this nearly human-sized