( 385 ) 

 ON THE EGGS OF THE TREE-PIPIT. 



BY 



PERCY F. BUNYARD, f.z.s., m.b.o.u. 



It is surely a little surprising that no one has yet seriously 

 attempted to analyse and systematise the marvellous range 

 of variation which the eggs of the Tree-Pipit {Anthus trivialis) 

 present, in the matter of colour and arrangement of 

 markings. How great is this range may be gathered from 

 the extremely divergent descriptions which have from time 

 to time been published by the various authors who have 

 had occasion to refer to this subject. 



It has been contended indeed that it is impossible to 

 define the limits of this variation. But with this view 

 I cannot agree. On the contrary, as I propose to show, the 

 apparent medley of colour and markings here presented can 

 be reduced to an orderly system comprising no less than seven 

 distinct types. This result, I need hardly say, could never 

 have been arrived at if I had not, through the kindness of 

 many friends, been enabled to examine a very large number 

 of specimens. These seven types (not varieties, be it noted) 

 are, in my opinion, of sufficiently frequent occurrence, and so 

 constant and well-defined as to justify this classification. 

 They may be divided into two classes, namely, mottled, 

 and spotted. I recognise three types of mottled eggs, 

 two of which are very distinct ; while in the spotted 

 eggs I can distinguish four types, three of which have very 

 strongly marked characteristics. It will be observed that I 

 have endeavoured to describe the extreme, and less modified, 

 forms of each of these ; varieties I have not in this paper 

 attempted to deal with ; though they are of frequent 

 occurrence they may, with a keen eye, and a little trouble, 

 be traced to one or other of the types just referred to. 



A few words in regard to the system upon which I have 

 worked to obtain these results may be of interest, though 

 I do not pretend that this system would be applicable to the 

 eggs of all species. The work of most importance is the 

 separation of the clutches into their respective types (by no 

 means a difficult operation), keeping them separate by placing 

 each type in a separate tray upon which wiiite cotton wool 

 has been carefully and evenly spread ; if glass-lid boxes are 

 used the lids should be removed before attempting to dis- 

 tinguish the colours ; always use a magnifying glass of low 

 power, which assists very materially in obtaining accuracy 



