The text for each species highlights the diagnostic feature or combination of features that will enable the birdwatcher to most easily identify the bird. Clear colour photographs have been chosen to illustrate the guide. For those species that are sexually dimorphic, have both breeding and non-breeding plumage, or in which the juvenile plumage differs markedly from that of the adult, more than one photograph has been included. Thumbnail silhouettes aid the reader in quickly locating the correct group of birds, and for each species account a map shows the bird's distribution.