84 THE PLUMAGE OF BIRDS 



Is it performed by one or both sexes? Is there any regularity in the daily 

 periods of sitting? Does one sex ever feed the other while on the nest? 

 Will the sitting bird permit a near approach? Does the bird return to the 

 nest directly or with much caution? Are the eggs turned in the nest? Are 

 they covered when left? How is the egg-shell disposed of after hatching? 

 The Young Bird. What is the condition of the young bird at birth? 

 If blind, when do the eyes open? What notes does it utter? How long is 

 it in the nest? How is it fed? on what? how often? Is the food prepared? 

 What prevents the young bird from being over-fed? At what rate does it 

 increase in weight? How is it brooded? How is the nest cleaned? Do the 

 young obey the parent? When is fear first shown? Is it instinctive? What 

 nest exercises are manifested? How long after leaving the nest is the young 

 bird dependent on the parents? What induces it to leave the nest? Does 

 it fly at once? Does it return to the nest? Does it frequent roosts? Does it 

 flock with other young or with adults or both? How do the parents protect 

 the young? 



REFERENCES 



(Restricted largely to the more recent studies of the nesting habits of 

 birds.) 



1844. RENNIE, J., Bird Architecture (London). 1878. ALLEN, J. A., 

 An Inadequate Theory of Birds' Nests, Bull. Nutt. Orn. Club, III, pp. 22- 

 32. 1900. CHAPMAN, F. M., Bird Studies with a Camera, 12mo., 218 pp. 

 ills., (Appleton). 1900. DUGMORE, A. R., Bird Homes, 4to., 183 pp., 

 ills., (Doubleday). 1902. JOB, H. K., Among the Water-Fowl, 12mo., 224 

 pp., ills., (Doubleday). 1905. JOB, H. K., Wild Wings, 8vo., 341 pp., 

 ills., (Houghton, Mifflin). 1905. HERRICK, F. H., Home Life of Wild 

 Birds, rev. ed., 255 pp., ills., (Putnam's). (Important.) 1907. FINLEY, 

 W.L., American Birds, 12mo., 256pp., ills., (Scribner's) . 1907. CHAPMAN, 

 F. M., Camps and Cruises of an Ornithologist, 8vo., 432 pp., illus., (Apple- 

 ton). 1908. WATSON. J. B., The Behavior of the Noddy and Sooty Terns, 

 Papers from Tortugas Lab. of Cam. Inst., II, pp. 189-255, (Important). 

 1910. HERRICK, F. H., Instinct and Intelligence in Birds, Pop. Sci. 

 Monthly, June, July, and August. 1911. HERRICK, F. H., Nests and 

 Nest-building in Birds, Journ. of Animal Behavior, Vol I, (Holt). 



THE PLUMAGE OF BIRDS 



The Molt 



Plumage Wear 



The Colors of Plumage 



Color and Age 



Color and Season 



Color and Sex 



Color and Climate 



Color and Concealment 



Banner Marks 



Albinism and Dichromatism 



Feathers are the only character which birds do not share with 

 other forms of life. No other animals are feathered and no birds are 

 featherless. 



It is apart from our object to describe here the development and 

 structure of feathers, but rather to discuss their function, as in their 



