Avian Biology, Volume II is a collection of papers that deals with the biology of birds such as their integumentary and respiratory systems. One paper describes the integument of birds that includes the skin, feathers, pterylosis, skin muscles, and other integumentary derivatives such as beaks, comb, claws, and spurs. The book explains the process of molting and the different generations of feathers; such molting is dependent on the wear and tear of the plumage, as well as hormonal changes. One author compares the blood vascular system of birds and mammals, and then gives a detailed description of avian hematology. Other papers deal with the respiratory functions, digestive system, and the nutritional needs of birds. Of interest is one author's description of the production of nutritive fluids, holocrine, which is secreted for the young. This secreted fluid contains about 23 percent protein, 10 percent fat, and no sugar. Unlike mammalian milk, it also contains cells. Another paper examines the intermediary metabolism of birds and the climatic effects on metabolism. This book is suitable for bird enthusiasts, zoologists, and avian biologists.