Is a platypus a bird

No. A platypus is a mammal which lays eggs. It is semiaquatic, and found in eastern Australia, including the island state of Tasmania. It has a flat tail, feet with sharp claws and retractable webbing, and a snout that resembles a duck's bill. It is sometimes call the duckbilled platypus, but not within Australia.

The reason the platypus may be mistaken for a bird is that it is one of only three species of egg-laying mammals, or monotremes. It is a mammal because it has fur, and because it feeds its young on mothers' milk.