2 44 FIRST LESSONS IN ZOOLOGY 



both males and females ma)' change their plumage (hence 

 color and markings) with the season. The seasonal 

 clianges of plumage accomplished by moulting may be 

 marked or hardly noticeable. "All birds get new suits 

 at least once a }'ear, changing in the fall. Some change 

 in the spring also, either partially or wholly, while others 

 have as many as three changes — perhaps, to a slight ex- 

 tent, a few more. ... It is claimed by some that now 

 all new colors arc acquired by moult, and by others that 

 in some instances (young hawks) an infusion or loss, as 

 the case may be, of pigment takes place as the feather 

 forms, and continues so long as it grows." 



There is much lack and uncertainty of knowledge con- 

 cerning the moulting and change of plumage by birds, 

 and careful observations by bird-students should be made 

 on the subject. 



The uses of colors and patterns in animals are dis- 

 cussed in Chapter XVIII. For accounts of the plumage 

 and color of birds see Chapter III in Chapman's " Bird- 

 Life," and Chapters VIII and IX in Baskett's "Story of 

 the Birds." 



Structure and habit In connection with learning the 



different kinds of birds in a locality, observations should 

 be made, and notes of them recorded, on their habits, 

 and on their external structure and its relation to the hab- 

 its of the bird. The interesting adaptation of structure to 

 special use is particularly well shown in the varying char- 

 acter of the bill and feet of birds. The various feeding 

 habits and uses of the feet of different birds are readil}' 

 observed, and the accompan)-ing modification of bills and 

 feet can be readily seen in birds either freshly killed or 

 preserved as " bird-skins." .Such skins may be made as 

 directed on p. 33.S, or ma}- be bought cheapl)^ of taxi- 

 dermists. A set of such skins, properly named, will be of 

 great help in studying birds, and should be in the high- 



