SIDE LIGHTS ON BIRDS 



coincidence — if, indeed, it be merely a coincidence. 

 The eggs of all the great singers, with few exceptions 

 (the song- thrush, for example) bear a strong resem- 

 blance to each other in colour. In the nightingale, 

 skylark, blackcap, garden-warbler, and many others 

 the same olive brown hue is repeated in lighter or 

 darker tones. It may also be noted that no bird 

 in our country which may be fairly classed as a 

 songster is produced from a white egg. Ducks 

 and geese, owls, wood-peckers, pigeons, swifts, 

 martins, kingfishers, wrynecks, in all these the notes 

 are either harsh or inconspicuous. Thus, it will 

 be seen that, although no definite theory can be 

 based on these facts, it would be rash to say that no 

 relation whatever exists between the coming chick 

 and the egg-shell in which it is enclosed. 



Another interesting fact that was remarked upon 

 by Hewitson as long ago as 1838, is that nearly 

 all birds which breed m holes, or m other places 

 from which light is excluded, lay imiformly white 

 eggs. This has given lise to many ingenious 

 theories. One hypothesis set forth by Dr. 

 M'Aldowie is that all eggs were originally coloured ; 

 that the pigments, unstable and variable, were 

 intended to assist in concealment and in protection 

 from solar rays, and that as the ages went by, in 

 the case of eggs laid in caves, holes, and other gloomy 

 recesses, these safeguards were useless, and so the 

 colouring disappeared. Newton, however, points 

 out one fatal objection to these and kindred specu- 

 lations. He shows that all these hypotheses are 

 based on a study of the eggs of British birds only, 

 and he remarks that as the most instructive forms 

 of each class do not belong to our own limited fauna, 

 allowance must be made for the imperfect informa- 

 tion whence the results a^e diawn. Still we think 

 the fact lemams that if the white, conspicuous eggs 



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