| Birds are warm-blooded, bipedal egg-laying | | | | habitats. With that aside there are others |
| vertebrates that are characterized primarily | | | | that will spend almost all their time at sea. |
| by their physical features of feathers, | | | | Some birds have the ability to stay up in the |
| forelimbs modified as wings, and hollow | | | | air for days at a time, even sleeping while |
| bones. Birds range largley in size from tiny | | | | in the air. |
| hummingbirds all the way up to the huge | | | | |
| Ostrich. Depending on how you look at it, and | | | | All birds have similar characterists: |
| what your viewpoints are there are | | | | |
| approximately ten thousand different species | | | | - Bony beak with no teeth |
| of living birds. Note the living. there are | | | | |
| several others that have become extinct | | | | - Laying of hard-shelled eggs for |
| throughout human history. This mass in | | | | reproduction |
| numbers makes birds the most diverse class of | | | | |
| terrestrial vertebrates. | | | | - high metabolic rate |
| | | | |
| Birds are at the majority of times a very | | | | - Light and strong skeleton |
| differentiated class, with some feeding on | | | | |
| nectar, plants, seeds, insects, rodents, | | | | Most birds also share the common trait of |
| fish, carrion, or other birds. Most birds are | | | | flight however there are sevaral species of |
| diurnal, which means that they are active | | | | flightless birds, that exist mostly on |
| during the day. Some wild birds, such as owls | | | | islands. These are birds that once used to |
| and nightjars, are nocturnal or crepuscular | | | | have the ability, but do to adaption have |
| which means that they are active during the | | | | lsost it. A famous flightless bird is the |
| night. Several birds will migrate long | | | | kiwi which exists in New Zealand. |
| distances to take advantage of optimal | | | | |