^6 Fifteenth Congress of the A. O. U. Ft n^ 



The first paper of the afternoon was ' The Great Roosts on 

 Gabberet Island, opposite North St. Louis,' by Otto Widmann. 

 In the absence of the author, it was read by Mr. Dutcher, who 

 also remarked upon the paper. 



The next title was 'The Terns of Gull Island, New York,' by 

 J. Harris Reed. As the author was not present, the paper was 

 read by Mr. Dutcher. Remarks followed by Messrs. Dutcher and 

 Chapman. 



The third paper, ' The Petrels of Southern California,' by A. W. 

 Anthony, was read in his absence by Mr. Chapman. Remarks 

 followed by Messrs. Chapman and Osgood, and Dr. Bishop. 



Then followed a paper by Rev. H. K. Job, entitled ' The 

 Northern Raven breeding in New England.' In the absence of 

 the author it was read by Mr. W. H. Osgood. 



Mr. Chapman gave further information regarding some of the 

 slides shown by him on the previous day. 



The fifth title was the ' Breeding Habits of the Common Robin 

 in Eastern Massachusetts,' by Reginald Heber Howe, Jr. The 

 author not being present the paper was read by Mr. Harry C. 

 Oberholser. Remarks followed by Messrs. J. Newton Baskett 

 and Louis Agassiz Fuertes. 



Mr. Abbott H. Thayer, the eminent portrait painter, then gave 

 an out-of-door demonstration of the underlying principle of pro- 

 tective coloration, in continuation of his remarks on the subject 

 at the previous Congress. Mr. Thayer showed a pair of decoys 

 with the belly part cut off, so that in lying on the cut-off side they 

 represented crouching birds or mammals. He then repeated 

 upon them the coloring which he had exhibited at Cambridge 

 upon entire decoys (decoys poised a few inches above the 

 ground) . This, he said, was to more clearly illustrate what he 

 stated in his first paper on protective coloration, namely, that the 

 normal gradation of the sky's lighting is effaced by the color grada- 

 tion of the animal at every point, the median dorsal line having the 

 darkest markings, so that the gradation toward the white of the 

 belly begins close to this dorsal line. Mr. Thayer placed the two 

 decoys side by side on a plank, and covered one of them uniformly 

 with the same dry earth which he spread about it on the plank, 

 so that all of its visible surface and that of the plank on which it 



