'1912 J Phillips, The Hawaiian Linnet. 337 



birds of ancestral stocks, it must behave as a dominant, or at least 

 as a partial dominant. Neither of the above premises is likely to 

 hold good. 



Now as to the value of these imported Hawaiian Linnets in a 

 racial sense. Mr. Grinnell discusses the change in caged Linnets 

 (University of Cal. Pub., Vol. 7, p. 179) and shows that yellow birds 

 result from red, after a short period of confinement. This appears 

 to be a well known fact with various red birds. The case of the 

 European Linnet is mentioned by Finn in the Avicultural Magazine 

 for June, 1906. Mr. Bangs informs me of like cases from his 

 own experience with Crossbills, Redpolls and Purple Finches and 

 with a Cardinal in confinement. The Cardinal did not go so far 

 off color as the Crossbills. The so-called Japanese Robin {Liothrix 

 luteus) which is brilliantly colored on the chest, throat, and pri- 

 maries with orange and scarlet-vermilion, turns more or less 

 olivaceous all over after a few moults according to Mr. Bang's 

 experience. We have all seen the dirty white color which American 

 Flamingoes take on in zoological gardens. 



Is it not thus highly probable, as Mr. Grinnell himself has 

 suggested, that a diminished tyrosine oxidation is responsible for 

 both the caged and the Hawaiian birds. The general environ- 

 mental complex of the Hawaiian Islands is an intricate problem, 

 but the fact that other American insular areas, Guadalupe and San 

 Benito Islands, show a rather high percentage of yellow or orange 

 birds is suggestive as Mr. Grinnell says of some special insular 

 effects. The occurrence of some yellow or orange birds (percent 

 hard to estimate for reasons given Mr. Grinnell on p. 182) in the 

 normal habitat of the species, shows that its color elaborator is in 

 a state of delicate adjustment, that is, it is not always allowed to 

 continue its action up to the ultimate crimson color. We can well 

 imagine, then, that a very slight diminution in the activity of the 

 enzyme might produce the observed results in Hawaii, and might 

 not these results be of entirely extrinsic origin? It is certainly 

 easier to apply a theory of this sort than to hunt about for a deeper 

 one. 



On page 184 Mr. Grinnell calls attention to the fact that eight or 

 ten years ago there were many red or crimson linnets in the islands. 

 The data upon which this suggestion is founded are not quite 



