102 



NESTLING BIRDS, AND SOME OF THE PROBLEMS 

 THEY PRESENT. 



BY 



W. P. PYCRAFT, A.L.S., F.Z.S., m.b.o.u. 



Part I. 



It is rather surprising that, while so much has been 

 written about British birds, so little has been said about 

 their nestling stages. 



Judging from the meagre descriptions which even the 

 best books give of nestling birds, we may assume that it 

 has been taken for granted that birds, at this early stage, 

 present no characters of suiiicient importance to warrant 

 closer study. That such a conclusion is not justified by 

 facts I hope to show in the course of the following 

 pages. 



To adaptation to environment we may probably attribute 

 the evolution of the two extreme types of nestlings to be 

 met with to-day— the active, down-clad type, and the type 

 which leaves the egg perfectly naked, and with sealed 

 eyelids, and which, in consequence, is for some time 

 absolutely helpless. 



Both these types, I need hardly remark, are to be met 

 with among our British birds ; j^et no one seems to 

 have realized what a rich field they present for investiga- 

 tion. No one, for example, seems to have made any 

 observations on the relative activity of such intermediate 

 types as young Gulls and Guillemots — a matter of more 

 importance than appears on the surface. Doubtless the 

 investigation of this matter wovild yield results but slowly, 

 and this is distinctly discouraging. 



Such an objection, however, will not appl}' to a 



