214 DARWINISM chap. 



huge goatsuckers — build very similar nests, and their white 

 eggs are protected in the same manner. Some large and 

 powerful birds, as the swans, herons, pelicans, cormorants, and 

 storks, lay white eggs in open nests ; but they keep careful 

 watch over them, and are able to drive away intruders. On 

 the whole, then, Ave see that, Avhile white eggs are conspicuous, 

 and therefore especially liable to attack by egg-eating animals, 

 they are concealed from observation in many and various ways. 

 We may, therefore, assume that, in cases .where there seems 

 to be no such concealment, we are too ignorant of the Avhole 

 of the conditions to form a correct judgment. 



We noAv come to the large class of coloured or richly 

 spotted eggs, and here Ave haA^e a more difficult task, though 

 many of them decidedly exhibit protective tints or markings. 

 There are tAvo birds Avhich nest on sandy shores — the lesser 

 tern and the ringed plover, — and both lay sand-coloured eggs, 

 the former spotted so as to harmonise Avith coarse shingle, the 

 latter minutely speckled like fine sand, which are the kinds 

 of ground the tAvo birds choose respectively for their nests. 

 "The common sandpipers' eggs assimilate so closely Anth 

 the tints around them as to make their discovery a matter 

 of no small difficulty, as every oologist can testify aa'Iio has 

 searched for them. The j^eAAdts' eggs, dark in ground 

 colour and boldly marked, are in strict harmony Avith the 

 sober tints of moor and falloA\^, and on this circumstance 

 alone their concealment and safety depend. The diA'ers' 

 eggs furnish another example of protective colour ; they 

 are generally laid close to the AA^ater's edge, amongst drift 

 and shingle, AAdiere their dark tints and black spots conceal 

 them by harmonising closely Avith surrounding objects. The 

 snij^es and the great army of sandpipers furnish innumer- 

 able instances of protectively coloured eggs. In all the 

 instances given the sitting - bird iuA^ariably leaves the eggs 

 uncovered Avhen it quits them, and consequently their safety 

 depends solely on the colours Avhich adorn them."^ The 

 Avonderful range of colour and marking in the eggs of the 

 guillemot may be imputed to the inaccessible rocks on Avhich 



•• C. Dixon, in Seebolnn's History of British Birds, vol. ii. Introduction, p. 

 x.xvi. Many of the other exanqjles here cited are taken from the same valu- 

 able v/ork. 



