°iSq6 J Chadbourxe on Individual Dickromatism. 223 



in tint that could be seen in almost every feather of the female. 

 On the other hand, it might perhaps be claimed that the total 

 number of feathers composing the plumage had increased, and 

 that the new phase was due to the freshly developed feathers 

 mingling with the old that had been present from the first. The 

 interest and importance of the change in tint of the female Owl 

 was now realized and a thorough search for pin-feathers was 

 made, but without success. Three of the feathers on the breast 

 that seemed without a trace of red or brown in the ground color, 

 were then marked with a pair of scissors to see if they would 

 remain unchanged, but within the next week I found all three 

 feathers on the floor of the cage ; two feathers around which I 

 tied a bit of hair, were also cast off or pulled out ; and the same 

 result followed with two feathers that were slightly marked with a 

 solution of eosine and water ; and also with two that were marked 

 with bi-chromate of potassium. There seemed to be only one 

 way left in which to settle the question as to whether the gray 

 feathers actually changed their tint; so having first 'mesmerized ' 

 (?) the owl by laying her on her back and gently stroking her 

 head until she was quiet, I carefully counted all the feathers hav- 

 ing a dark median stripe, but without any red or brownish tinge 

 in the ground color, beginning just below the whitish feathers of 

 the throat and going as far as the under tail-coverts, and from 

 the median line of the body to the unstreaked downy feathers 

 under the wing ; the result was forty gray feathers. Only three 

 weeks later, on Dec. 21, I could not find more than nine feathers 

 that were free from brownish tinge. It must, I think, be admitted 

 (1) that an actual change from gray to red-brown took place in the 

 individual feathers, and (2) that the red phase was not entirely, 

 if at all, due to new feather growth in the present instance. 



Until December 22, the diet of beef liver was continued, but was 

 occasionally varied by beef kidney, the other conditions remaining 

 as before. The larger Owl continued to approach more and more 

 nearly the red-brown phase, and on Dec. 2 1 had the general 

 tawny-brown effect seen in specimens that do not show the bril- 

 liant red, typical of extreme examples of this phase. Both birds 

 seemed healthy and well ; but the smaller Owl now also showed 

 more or less signs of reddish-brown here and there, and some 



