The blue peacock’s body feathers are mostly metallic blue-green. The green peacock, with a train much like that of the blue, has green and bronze body feathers. Hens of both species are green and brown and are almost as big as the male but lack the train and the head ornament. In the wild, both species live in open lowland forests, flocking by day and roosting high in trees at night. During the breeding season, the male forms a harem of two to five hens, each of which lays four to eight whitish eggs in a depression in the ground. The eggs are incubated by the peahen until they hatch some 28 days later. The chicks have all of their feathers when they emerge from their eggs and are capable of flight roughly one week after hatching. Most blue and green peafowl become sexually mature at age three. However, some male blue peafowl have been known to breed as early as age two.
Common bird names, such as Song Sparrow or European Starling, sometimes vary from place to place. A species that occurs in Europe and Africa may have different names on the two continents, or the same species may have different names in East Africa and Southern Africa. There are ongoing attempts to standardize such English names, but not yet universal agreement. Scientific names are less variable, but they sometimes change as researchers make new classification decisions. For example, the same bird species may have different genus names depending on the source consulted. The names I have used in this book, both common and scientific, come mainly from Lynx Edicions Handbook of the Birds of the World or the 5th edition of J. F. Clements, Birds of the World: A Checklist. There is also controversy over how best to write compound bird names, for example, Wompoo Fruit Dove, Wompoo Fruit-dove, or Wompoo Fruit-Dove. I’ve tried to be consistent in these kinds of names, but for this book’s purposes, such minute details are of minimal concern. Diversity The words diverse and diversity are used in different ways in various scientific and technical fields. Here, a diverse group, such as a diverse family, means one with a relatively high number of species. Thus, the loon family (Gaviidae), with a global total of 5 species, is not very diverse; the duck, geese, and swan family (Anatidae), with 157 species, has a high degree of diversity. Diversity, when used in this context, is similar to the term biodiversity, which refers to the different types of animals, plants, and other life forms found within a region. A group or family that is “ecologically diverse” is one that exhibits many different adaptations to the environments in which its members occur. For instance, an ecologically diverse group, such as the jay and crow family (Corvidae), might occur in several different habitat types, eat various types of foods, and employ a variety of foraging methods.
When I provide a definite number of species in a given family, such as “there are 10 species of motmots,” I mean there are 10 living species; recently extinct species are not included in these totals. Often I do not give exact numbers of species; instead I give approximations, such as “there are about 118 species in the jay and crow family.” For reasons I detail in the book’s concluding essay, exact species numbers are sometimes problematic.
On the color plates, I provide general natural ranges for each illustrated species, usually in terms of continents on which various species occur. Ranges for migratory species usually include both breeding and nonbreeding locations. A range given as “North America, South America” generally includes Central America.