[wendy1946]

The pterosaur's wingspan and size have spawned comparisons to dragons. But recently some scientists wondered whether the creature was too big to fly.

Face it, he was. At least in our world, the heaviest creatures which can take off and land go around 25 lbs and those can barely take off or land. The biggest pterosaurs would go around 1000 lbs in our world, and would never get off the ground. In the present age of the world, birds over the sizes of albatrosses and the largest buzzards long since lost their ability to fly and their wings became vestigial.

[txhurl]

You have to figure in thermas, updrafts of wind the today’s buzzards take use of.

[rmlew]

Haast’s eagle (Harpagornis moorei) from New Zealand weighed 18kg (~43 pound). They ate Moa and Maori, until the Maori killed them off about 600 years ago.