Summary:
- There are about 10,000 living species of birds.
- Almost all of them can fly, but there are several exceptions.
- Flightless birds include the ostrich, kiwi, rhea, cassowary, and moa.
- The most common orders include landfowl, waterfowl and nocturnal raptors.
- There are also flightless birds, birds that live near water, and parrots.
- The order of perching birds has more species than all the other bird orders combined.