1311] GrinneU: The Linnet of the Hawaiian Islands. 187 



As is very well known, California linnets, when placed in 

 confinement and originally red, become yellow with successive 

 molts during the life of the individual. I am informed by two 

 dealers in caged birds that adult male linnets (of the normal 

 plumage) when trapped and kept in confinement remain red for 

 two years, when abruptly, at the time of molt, they become dull 

 yellow (with no intervening orange stage). When sold for 

 plumage, it is thus desirable from the dealer's standpoint that 

 their linnets be sold out before the inevitable de-coloration. 



Mr. Loye Holmes IMiller contributes the following suggestions 

 to the present discussion : "The ^Mexicans of Arizona and Lower 

 California are especially fond of keeping the species in captivity, 

 and almost invariably the effect is to turn the plumage yellow. 

 One individual whose history I obtained made the change from 

 red to .yellow at the age of three years. Reared in captivity, it 

 assumed the red phase first, then during its fourth year changed 

 to the yellow phase. Is it not barely possible that the Hawaiian- 

 born birds, affected in some similar way by the changed environ- 

 ment, assume the yellow plumage at a more or less advanced age ? 

 The longevity of the individual would in this way influence the 

 ratio of yellow to red forms. The absence of birds of prey in 

 the Islands might again conduce to greater longevity; so that 

 the introduction of the factor of senility might further com- 

 plicate the problem." 



It would seem, however, from the fact that all the male lin- 

 nets obtained or seen in the Hawaiian Islands in 1910 are off- 

 color, that age alone in the individual could have little to do 

 with this condition of affairs, at least at the present time. It 

 would be extremely improbable that no birds-of-the-year should 

 be encountered among so many individuals, when ordinarily, 

 among passerine birds in the winter, birds-of-the-year are in the 

 majority. 



While results seem to have been brought about through a 

 series of generations of the Hawaiian birds similar to those 

 occurring within the lifetime of a caged linnet, it does not neces- 

 sarily follow that the same initial cause or successive processes 

 were or are operative in the two cases. Still, this is a reasonable 

 inference. Experimentation on linnets in confinement, in which 



