Birds That Can't Fly?

Did you know...
There are many birds that can't fly. Does that make you wonder why they are called birds? When you think of a bird do you not think of one that can soar high above the trees? Is it a bird just because it has feathers? I guess our scientist think so but did you know why these birds can't fly?

It is believed by some that most flightless birds evolved in the absence of predators, on deserted islands, and lost the power of flight because they had few enemies — although this is likely not the case for the ratites; the ostrich, emu and cassowary, as these all have claws on their feet which can be use as weapons against predators.

The 2 key differences between flying and flightless birds are the smaller wing bones of flightless birds and the absent (or greatly reduced) keel* on their breastbone. The keel anchors muscles needed for wing movement. Flightless birds also have more feathers than flying birds. This and perhaps their weight has something to do with them being flightless. There have been over 40 recorded birds that can not fly. Some are extinct now. The last known ones that still live and most people know are the many varieties of the Penguins, Emu and the Ostrich. The smallest flightless bird is the Inaccessible Island Rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the Ostrich (2.7 m, 156 kg) (although some extinct species did grow to a larger sizes). Ostriches were once farmed for their decorative feathers. Today they are raised for meat and for their skins, which are used to make leather. The Emu is also being used for a source of food as well as their oils in a topical applied pain reliever.

*A keel in bird anatomy is an extension of the sternum which runs axially along the mid-line of the sternum and extends outward, perpendicular to the plane of the ribs. The keel provides an anchor to which a bird's wing muscles attach, thereby providing adequate leverage for flight. Keels do not exist on all birds; in particular, some flightless birds lack a keel structure.