i o Introduction 



Age of a Feather. After a feather attains its maturity the contents of the 

 quill dry up and it is incapable of further development. It becomes, so to speak, 

 "dead." A great deal has been written to prove the contrary; namely, that a 

 feather may, after it reaches its maturity and does duty for a varying length of 

 time, again take on a period of active growth and change. This is to account for 

 certain so-called "changes of plumage without moult." But it seems to be now 

 settled beyond any reasonable doubt that when a feather completes its growth, 

 and the contents of the quill become dry and "lifeless," it can never reinaugurate 

 the process. There may be a fading or bleaching, or the outer extremities of the 

 feather may be abraded in one manner or another, resulting oftentimes in a 

 freshening or brightening of the plumage, as for example in the spring plumage 

 of Purple Finches, Crossbills, etc., but this is quite different from a renewed 

 growth and repigmentation of the individual feathers. This brightening of the 

 plumage in the above-mentioned species was long ago shown to result from the 

 fact that the winter feathers have red barbs and gray barbules, and on the latter 

 wearing away, the red elements of the feather are exposed. Beyond these rela- 

 tively slight changes by abrasion or disintegration of the tips, or by fading, change 

 of plumage can only result from moult. 



It is only within the last few years that any extended researches have been 

 undertaken in this country with a view of elucidating the sequence of plumages 

 and moults in our birds, and while an extensive body of facts has been accumu- 

 lated, much still remains unknown. Those who wish to look further into this 

 subject should consult the papers mentioned below by Witmer Stone 1 and 

 Dr. Jonathan Dwight, Jr. 2 The latter author has placed the terminology of the 

 subject on a uniform and logical basis. His scheme will be understood from the 

 following tabular arrangement : 



PLUMAGES MOULTS 



1. Natal (Down). i. Postnatal. 



2. Juvenal ('First plumage'). 2. Postjuvenal. 



3. First winter. 3. First prenuptial. 



4. First nuptial. 4. First postnuptial. 



5. Second or adult winter. 5. Second or adult prenuptial. 



6. Second or adult nuptial. 6. Second or adult postnuptial. 



Nests and Eggs of Birds. A word should perhaps be said in regard to the 

 nests and eggs of birds, but in the space at command it can be but the briefest 

 outline of a broad and extremely complicated field. It is perhaps unnecessary to 

 state that all existing birds, without a known exception, lay eggs. To a casual 

 observer, viewing a large collection of birds' eggs, the variation in size, shape, 

 color, markings, etc., seems almost infinite. For the differences in size he is 



1 " The Moulting of Birds with Special Reference to the Plumages of the Smaller Land Birds 

 of Eastern North America," Proc. Acad. Nat. Sci. Phila., 1896, pp. 105-165. 



2 "The Sequence of Plumages and Moults of the Passerine Birds of New York," Ann. N. Y. 

 Acad. Sci., vol. 13, 1900, pp. 73-360, plates 1-7. 



