Birds are defined as warm-blooded vertebrates. They have feathers, toothless beaked jaws, a high metabolic rate, a 4 chamber heart, a strong and lightweight skeleton and the laying of hard-shelled eggs.

Now, within these constraints, the birds vary a great deal.

The smallest bird is the bee hummingbird, which has a wingspan of 6.8cm. The largest bird has a wingspan of 3.5m (40 times large). In terms of weight, the bee hummingbird is also the lightest at just 1.95 grams, the Kori bustard weighs as much as 19kg, which is almost 10000 times heavier (heaviest flying bird). The heaviest bird is the Ostrich, which can weigh over 100kg, though these can not fly.

Looking at it in a different way, there are roughly 10,000 species of birds in the world. Now, while this may change as this website grows (both with other authors, and assistance from readers) at the current time, it would be absurd to think that I could build a page for each of these many species. What this page will try to do, is to build a page for each group of birds. Of course, the other point of this website, is that this is to assist in people travelling to see these species in the wild. As such, while I am fully of the opinion that every bird matters, we will concentrate- to begin with, on birds which are popular and/or are interesting to see.

To start, below you will see the initial 2 clades (it should be noted that there was at one time 7 clades, which include clades like Diosaruia), and each clade has two families. 

                                   Palaeognathae (ratites and Tinamou)                                                                                                               Neognathae