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small seeds, and food prepared with egg when feeding 

 young. They hybridize with several British finches, 

 the Goldfinch being chiefly used to mate with them, 

 but the hybrids are, usually at all events, sterile. It 

 is the great desire of hybrid-breeders to obtain hen 

 Canaries which, when paired to a Goldfinch, will pro- 

 duce a yellow hybrid, such hybrids being very rare 

 and valuable, though dark ones are easily bred. Of 

 course, what is wanted is prepotence in the the hens, 

 and by careful breeding on Mendelian lines such 

 birds might be obtained. It this were done the profit 

 from the sale of these and their hybrids would be very 

 large. As Goldfinches will breed in captivity some 

 attempt might be made to produce a " muling strain " 

 from them also. They need much the same treatment 

 as Canaries, and will live with them. The song of the 

 cock Canary is known to have great influence over 

 the hens, and experiments might be s}^stematically 

 conducted on this point. Common mongrel Canaries 

 of no particular breed are best for bionomical pur- 

 poses, and of these cocks cost about 5s. and hens 

 about half as much. 



The Common Greenfinch is the easiest British 

 finch to breed, and is very cheap, almost valueless in 

 fact. Fanciers, however, distinguish between a " buff" 

 and "jonque" form of bird (these terms, denoting 

 intensity of colour, applying to dark as well as yellow 

 birds) : the inheritance of these wild variations and 

 their sexually selective value should be investigated. 

 Greenfinches should be treated like Canaries, but not 

 kept with them, but rather with Budgerigars and Java 

 Sparrows, as they are strong and rather vicious birds. 

 Greenfinches ought not to cost more than 6d. each. 



The House-Sparrow sometimes produces white, 

 cinnamon, and pied forms, and these should be ex- 

 perimentally investigated. The bird will breed in 

 captivity, and should be kept with and treated like 



