9 2 



years ago Mr. C. Swailes recorded that he had tried to produce 

 light coloured Redpolls by pairing and breeding from white and 

 cinnamon one, but could never get anything different from the 

 normal form. I had a similiar experience myself in Calcutta. I 

 once procured, at about the same time, a cinnamon cock Sparrow 

 and a white hen ; these I gave to a friend, who had an aviary, 

 and the birds bred there, but the young one produced was a dis- 

 appointment, as it was hardly lighter than an ordinary Common 

 Sparrow. 



White or light colours must be very easily bred in some 

 cases. We have white varieties of all our poultry, and among 

 Cage Birds, in the Java Sparrow, Bengalee and domestic Dove ; 

 while in addition to the yellow Canaries, of late years, yellow 

 Budgerigars have been raised, of course, also, all the abnormali- 

 ties which make many of our domestic birds so remarkable have 

 been produced by breeding from specimens varying in colour 

 or form. 



It naturally occurs to everyone to ask what is the cause of 

 appearance of variations, and so far the only answer to this is 

 simply that we do not know. What causes variations is, in fact, 

 now the chief problem of biological science. Fanciers had proved, 

 long before the evolution theory was worked out by Darwin, that 

 once variations have appeared, and these happen to be hereditary, 

 form and colour can be modified to an enormous extent, but how 

 these variations are produced in the first place is a real mystery 

 of nature. There would, however, seem to be a close connection 

 between some forms of variations and local constitutional dis- 

 turbance. The fact that pale colours appear if a bird, through 

 advancing age or indisposition is in low condition during the 

 moult, is an indication of this, and in this connection it may be 

 observed that light colour-varieties are often found to be weaker 

 in constitution and softer in feather than the normal types. In 

 may here be asked, how, in this case (supposing white forms to 

 come, as appears to have always been the case, from coloured 

 ancestors), white species of birds have arisen at all ? But in 

 answer to this, it may be pointed out that it is quite possible for 

 an individual or species to be weak in one respect and strong in 

 another. There is a case on record of a pied cock Blackbird 



