Surprisingly, the size of a bird will often help in identifying a new bird even more than color. Comparing an unknown bird to another bird we are all familiar with is easy and remarkably accurate. In your field guide, measurements are from the tip of the beak to the tip of the tail, when the bird is lying flat on its back. For birds with very long legs or necks, these measurements can be deceiving. In that case, it may be better to refer to the overall size of the bird's body.
Most observers tend to overestimate the size of a bird.
He then shares his field identification expertise by providing simplified tips on finding and identifying all species that can be seen in North America. Warblers of North America Each of the 60 species is described in detail, from field marks to mating habits. Every plumage is beautifully illustrated in color. The Identify feature lets users enter the size of the bird seen, as well as color, habitat and location. Photos and songs appear for all birds that match the description given.