AN ORIGINAL GUILLEMOT 145 



which the colouring tends to concentrate in a 

 belt or cap, almost invariably at the large end — 

 phenomena which are well exhibited in the common 

 Sparrow. No other bird is anything like so variable 

 in its egg-coloration as the Guillemots, but some 

 are very far from being even ordinarily true to 

 type, as the Red-backed Shrike with its olive and 

 red types, some Indian Warblers with their blues and 

 reds, and some of the Africaii Weavers with their 

 self-blues, spotted blues, and whites. 



Individual birds, however, tend to reproduce the 

 same type of egg ; there is an historical instance of 

 a Guillemot which laid on a particular rock-shelf an 

 egg of the rare and valuable red variety which was 

 duly taken for fifteen years on end — though of 

 course this might have been the produce of another 

 bird with the same peculiarity. Yet on the other 

 hand, all the eggs in a laying may not match ; the 

 Tree-Sparrow is notorious for having one differently 

 marked egg in every set, and the Golden Eagle 

 commonly lays one variegated egg and one plain 

 one. It is said, also, that in the case of birds which 

 lay richly coloured eggs, the coloration varies as 

 the bird advances in years, which is, after aU, rather 

 what one might expect. 



The colour is in any case laid on almost like 

 paint, and will smear if the egg be washed when 

 new-laid ; while in the case of the eggs of many 

 groups — Shore-birds (fiharadriides). Gulls, Rails, 

 and song-birds especially — it will be noted that 

 there are often two sets of spots, one of which 

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