NOTES ON THE HYBEIDS BETWEEN THE 

 CANAEY AND TWO AMEEICAN 

 FINCHES 



O. E. PLATH 



Massachusetts Institute of Technology, Cambridge, Mass. 



Perhaps no animal has been so often crossed with other 

 species, and even genera, as the domesticated canary 

 {Serinus canarius), Darwin (1885, I, p. 311) speaks of 

 "nine or ten" such crosses, but many more have un- 

 doubtedly been made. The hybrids resulting from these 

 crosses are usually, if not always, infertile, and hence 

 are popularly known as ''mules." In almost all of these 

 crosses the domesticated canary serves as the female and 

 the wild finch as the male, but bird fanciers occasionally 

 succeed in making the reverse cross. The wild species 

 which is most commonly used for this ''mule breeding" 

 is the European goldfinch, Carduelis carduelis Linnaeus.^ 



This fringillid is one of the handsomest finches in ex- 

 istence, the plumage of the adults of both sexes being 

 made up of a beautiful combination of black, red, white, 

 yellow, and brown patches. The hybrids which result 

 when a yellow, or nearly yellow, canary is crossed with 

 this finch are chiefly interesting for two reasons: (1) 

 because they exhibit an apparently endless chain of 

 variability in coloration, and (2) because their plumage, 

 if dark, is conspicuously streaked, a character which is 

 lacking (as far as external appearance is concerned) in 

 both the yellow canary and the European goldfinch. 



Concerning the first of these two points valuable data 

 have been published by Bechstein (1795), Hiinefeld 

 (1864), Blakston (1880!), Klatt (1901), Davenport 



1 According to Chapman (1916, p. 383), this finch was introduced into 

 the United States at Hoboken, N. J. (in 1878), and Boston, and probably 



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