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NESTLING BIRDS, AND SOME OF THE PROBLEMS 

 THEY PRESENT. 



BY 



W. P. PYCRAPT, A.L.S., r.z.s., m.b.o.u. 

 Part III. 



(Continued from page 132.) 

 (Plate IV.) 



We must pass now to the subject of the composition of 

 the nestling clown, about which by no means everything 

 is known. 



In the first place two quite different kinds of down are 

 to be distinguished : (1) the down-feathers that precede, 

 and are replaced by, the contour-feathers ; such down- 

 feathers I call pre-pennce, and (2) the down-feathers which 

 precede and are replaced by adult down-feathers ; the 

 down-feathers of this order I call pre-plumulce. 



To show the importance of this distinction I may cite, 

 by way of illustration, the fact that the Owls and Hawks 

 are, in the nature of their nestling-down entirely different 

 one from another, for while in the Owls this down is 

 represented by pre-pennce only, in the Hawks it is composed 

 of a mixture of both forms. More than this, if a young 

 Hawk, of any species, be carefully examined, it will be 

 found that the pre-pennce are relatively feebly developed, 

 while the pre-plumulce are of considerable size, and make 

 up the bulk of the downy plumage. This being so, it is 

 not surprising to meet with instances wherein the jsre- 

 pennce have been suppressed, so that the whole downy 

 covering is composed of pre-plumulce alone. This obtains 

 in the young Cormorant for example. 



Pre-plumulce occur only in birds which have a sort of 



