4:1 



When egging at St. Albans Head I have been struck with 

 the fact that the well-known blue variety of the guillemot seems 

 always to be laid on a more exposed ledge of rock than the 

 others, with more or less sky above, and sea all around, so in 

 colour like its surroundings, but by no means a protective one, 

 though some guillemots' eggs exactly resemble the greyish and 

 yellowish cliffs they are on. Following the same line of argu- 

 ment the blue colourings on eggs would be derived from the 

 sea or sky. Quite blue, like all the family of long-necked 

 herons', with an uninterrupted view of the heavens. Spotted 

 (like, say a blackbird's), when the sky is seen through foliage. 

 It is true some few birds in covered nests lay blue eggs, 

 but for a long time I have said starlings may, perhaps, 

 lay their eggs on the ground and deposit them afterwards 

 in a hole, and for the reason that every year I pick up so 

 many starlings' eggs on the ground, and always right in 

 the open ; and also because at Owsden Hall, on 29th April, 

 1894, I saw one fly to a hole, high up in an elm tree, 

 with an egg in its mouth. It flew out again and dropped the 

 egg, which I picked up and have now in my collection. It was 

 a perfectly fresh and uninjured starling's egg. A redstart, so 

 fond of a gate-post, may get an uninterrupted view straight up, 

 and in the same way a jackdaw may get an interrupted view with 

 patches of black. Cuckoos' eggs, with their extraordinary 

 diversity of colour, would be accounted for by the great 

 diversity in the colour of ground upon which the eggs are 

 laid, and the blue variety, either from the rare blue male bird, or 

 perhaps from the sky. The gay plumage of female birds would 

 be obtained from the males, whether in a covered nest or not, 

 that is to say, their bright colouring would overcome the colour 

 of surroundings. This would also apply to all birds nesting in 

 colonies, such as rooks, herons, gulls, guillemots, swifts, swallows, 

 martins, etc., where the two sexes are always alike in colouring, 

 because here the number, all with the same colouring, would 

 make up for a dull plumage and so again overcome the colour 

 of the surroundings, and, as I mentioned before, would account 

 for the sexes being alike in colour in all animal life that con- 

 gregated together. 



In polygamy the same hen would so seldom see the cock, 

 that bright colouring would not come in, and she would more 

 likely resemble her surroundings, as females of pheasants, 

 peacocks, etc. In the ducks the case is reversed, as the males 



