307. In what way are birds unlike any other member of the animal kingdom? Of all forms of animal life on this earth, birds and only birds have feathers. All birds possess them.
311. From an engineering standpoint, what are the chief characteristics of a feather? A feather is the most complex growth of skin known to be formed by any animal. It is one of the lightest and at the same time one of the strongest materials formed by any creature. It is durable, complex and flexible, a superb functional structure for both flight and heat retention.
312. How many feathers does a bird have? The number of feathers a bird has usually increases with its size. Summer counts on a hummingbird indicate that it has about 1,500 feathers at that period. A robin has almost 3,000 feathers while a whistling swan has more than 25,000.
Illustrations (upper to lower):
Albrecht Durer, Wing of a Blue Roller, 1512, Gouache and watercolor on vellum, Graphische Sammlung Albertina
New Guinea Parrot
Upper and lower surfaces of a rock dove's wing, diagrams from Pettingill, Jr. 1985
Hummingbird
American Robin
Whistling Swan
Text from: 1001 Questions Answered About Birds by Allan D. Cruickshank and Helen G. Cruickshank (Toronto, General Publishing Company, 1958)
No comments:
Post a Comment