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 x4 THE CONDOR [ Vol. iii managed to get six of these. Two are in immature plumage, one shows an in- clination to orange, and three have yel- low in patches. Pains have been taken to make this list in some detail in order to show how frequent is the tendency to yellow; so frequent is it that we are hardly justi- fied in calling it an abnormal condition. The hypothesis that yellow is a more primitive color than red finds additional evidence in another genus, Cfanospiza. A spring male of C. ciris taken in Georgia has one yellow feather in its breast and five in its throat. Another male of this species shows yellow on the flank. x That these facts point to an ancestral bird of yellow plumage seems most reasonable to answer a question as to why so many birds are off color. Mr. Charles A. Keeler has suggested that yellow is the more primitive color and red an intensification of the same pigment, although he gives no experi- mental data to support his opinion. So high an authority as Dr. R. W. Shu- feldt wrote me, October o, 899, in re- gard to this subject: "I am inclined to agree with Mr. Keeler that fellow birds preceded red ones in the history of the group in time, and thus viewed, red nay be but an intensification of the former color." Mr. J. Armory Jefferies says: "Red feathers as those of the Flamingo, Cardinal Bird, and the like, are so col- ored by a red pigment similar to the yellow one. " Keelera has called attention also to the factthat the House Finch when kept in captivity changes from red to yellow, and that 4"many birds appear to become more brilliant in color as the breeding season approaches without either a moult or the wearing away of the tips of the feathers." This last point is indicated by the series of finches in my collection. He says:* "It is difficult to say whether the change in color of the caged house finch (Carpodacus mexicanus frontalis) from red to yellow is due principally to a change in food, or to the confinement and general deterioration of the system from captivity. Food nevertheless, plays some part in this, as well as in ninny changes in the color of birds in the wild state, which, with the present lack of experimental data, are far too complex even to be surmised. "6 I have quoted at length from Keeler in order to emphasize the richness of material ready to our hand. Here is an excellent chance for interesting and valuable experimentation. A study of the color change in our commonest bird would give big returns for the time in- vested. For such work, however, one should be permanently located where continuous out-of-door work might be done for a year or more. One more extract from Keeler's work may not be out of place. "The most significant interrelation of colors, how- ever, and one which I believe to be of wide application in the explanation of bird colors, is that between yellow and red. Whether these two colors are pro- duced by the same or a different pig- lnent I am unable to say; but, however this may be, there is a 'high degree of probability that the red is simply an in- tensification of the yellow. There is much to show that yellow is a more primitive stage than red, and that the latter has always or nearly always been developed from the former."* It is to be hoped that someone who has time and facilities will feel enough interest in this matter to make at least a study of the moult and of the effect of food supply, varied as to quantity and and quality. x. NOTE--Since writing the above I have examined a beautiful series of Hawaiian Island species, VesNara cocc- inea, iu the collection of Mr. H. W. Henshaw of Hilo. In the adult plumage this bird is entirely red. The young, however, are yellow and Mr. Henshaw's lot shows the gradual change from yellow to red. e. Bull. Nut. Ornith. Club. VII. P. 3 I. 3. Evolution of Colors of N. A. l,and Bds. P 56. 4- l.c.p. i36. 5. 1. c. p. 229. 6. See on this subject, Birtwell, Auk XVI. p. 33. 7.1. c. p. I54.