As you begin to get to know the seventy-five birds in this book, it’s helpful to understand how they are organized. Generally, this guide and most others are organized in taxonomic order, which reflects the order in which the species evolved. Ornithologists recognize two main groups of birds—the “non-passerines” and the “passerines”; we treat the non-passerine birds first because they are the modern descendents of the first birds to split off the evolutionary tree.
HERE’S A LITTLE BACKGROUND: THE FIRST BIRDS EMERGED from the reptile lineage about a hundred fifty million years ago, and although many of those ancient avian beginnings became dead ends, one group survived to become today’s birds, a group that now seems most likely to have had its roots in the dinosaurs. Indeed, recently discovered fossils of dinosaurs with feather coverings help confirm that birds are modern dinosaurs with feathers.
But we classify modern birds into the class Aves, distinguishing them from the dinosaurs’ class Reptilia and recognizing about ten thousand bird species worldwide in about thirty major groups. Some of the first birds to split from the lineage leading to modern birds were ostriches, emus, and their relatives, none of which occur in North America. The next two groups to have split off are believed to be the waterfowl (ducks and geese) and the gallinaceous birds (quail and other chicken-like birds), so they are listed first in this book.
Of the seventy-five birds treated in this book, the last fifty-nine belong to the wildly successful and more recently evolved group of birds called “passerines” (see pages 56–57 for an overview). Passerines are often called “the perching birds,” though other birds also perch, of course; ornithologists recognize them as a group because of the unique structure of their toes and leg bones. The first sixteen species in this book belong to a set of other groups typically referred to collectively as “non-passerines.” Among the non-passerine groups represented in this first section of the book are the ducks and geese, quail, grebes, hawks, rails, cranes, shorebirds, doves, owls, nightjars, hummingbirds, kingfishers, and woodpeckers—representatives from thirteen of the world’s non-passerine groups.
Vocalizations of these non-passerines include some of the best-known and favorite sounds in our avian soundscape. What child doesn’t know how to quack like a duck or hoot like an owl, and the asthmatic, raw-power scream of a Red-tailed Hawk is dubbed into almost every movie wilderness scene. Among fifteen of the sixteen species represented here, it is believed that the sounds that they use are inherited from their parents, with the instructions on how to use the appropriate sounds somehow encoded in the genetic material. The one fascinating exception is the hummingbird.
The vocalizations of these non-passerine examples illustrate well the ways in which sounds are important in the daily lives of these diverse birds. Come listen in a whole new way to the quacking of ducks and honking of geese, to how a snipe sings with its tail and a nightjar with its wings, to how woodpeckers “sing” by ramming their bills into trees.