Amazingly, biologists estimate that there are over 9.700 species of birds in the world! By location, the number of species breaks down as follows:
3,200 South America
2,000 North and Central America, Caribbean
1,700 Australia and surrounding islands
Of the 3,200 species found in South America, the highest concentration of bird species is found in just three countries - Columbia, Bolivia and Peru. In those countries the count for each country is estimated at over 1,700 species. Compare this with only 950 species found in the whole of the United States and Canada!
Until fairly recently the classification of birds was based primarily on morphological characteristics. In the last decade, however, work using DNA has given biologists a more accurate way of identifying the affinities (or likenesses) between the different bird families.
Birds form the class Aves of the phylum Chordata. There are two subclasses: Archaeornithes, which consists entirely of extinct birds and Neornithes, which includes three superorders:
I. Odontognathae. Extinct birds that had teeth. Examples are the ichthyornis and hesperornis.
II. Impennes. This consists of only one living order, Sphenisciformes, or penguins.
III. Neognathae. There are either 28 or 29 orders to this superorder (depending on how 12 is classified). They are:
1. Struthioniformes, ostriches.
2. Rheiformes, rheas.
3. Casuariiformes, cassowaries and emus.
4. Dinornithiformes, the moas; extinct.
5. Apterygiformes, the kiwis.
6. Tinamiformes, primitive fliers. (All the birds previously listed are flightless.) An example is the tinamou.
7. Gaviiformes, freshwater diving birds with pointed bills and webbed feet.
8. Colymbiformes, or Podicipidiformes, freshwater diving birds with pointed bills and lobed feet.
9. Procellariiformes, seabirds that are strong fliers with webbed feet.
10. Pelecaniformes, pelicans and their relatives.
11. Ciconiiformes, wading birds with long necks and long legs.
11A. Phoenicopteriformes, flamingos. They are sometimes grouped with the Ciconiiformes, sometimes as a separate order.
12. Anseriformes, waterfowl.
13. Falconiformes, day-flying birds of prey.
14. Galliformes, domestic and wild fowl.
15. Gruiformes, long-legged birds with bare foreheads.
16. Diatrymiformes, large, extinct birds; found only as fossils.
17. Charadriiformes, shorebirds; live on or near water; few other characteristics in common.
18. Columbiformes, pigeons and their relatives.
19. Psittaciformes, parrots.
20. Cuculiformes, cuckoos and their relatives.
21. Strigiformes, owls.
22. Caprimulgiformes, birds with small bills but large mouths; feed on insects in flight.
23. Apodiformes (formerly Micropodiformes), swifts and hummingbirds.
24. Coliiformes, African birds that creep among tree twigs where they feed on fruit. The common name is mousebird.
25. Trogoniformes, birds with long tail coverts and beautiful plumage; live in forests.
26. Coraciiformes, brightly colored birds with short legs and long bills.
27. Piciformes, woodpeckers and their relatives.
28. Passeriformes, perching song birds