226 McAtee, Recognition Marks. [^ril 



season is over, because of their molesting the later varieties it 

 would seem quite as justifiable to shoot them early enough to save 

 the Campbell's Early grapes also. It seems a pity to be compelled 

 to kill such wonderful singers as Sage Thrashers, birds, which, were 

 it not for their grape eating habits, would undoubtedly be very 

 beneficial, but no better method occurs to me and it is difficult to 

 stand by and not try to save the grapes. 



In the few isolated vineyards in this lower Yakima Valley the 

 killing of the Thrashers, which infest them during the grape season 

 would evidently save the grapes and, because the Thrashers do not 

 fly about the valley in flocks, only the few which live in each 

 vineyard would have to be destroyed. This would save the grapes, 

 and would probably not appreciably effect the total number of 

 Thrashers inhabiting the valley. 



CERTAIN PHASES OF THE THEORY OF RECOGNITION 



MARKS. 



BY W. L. MCATEE. 



The paper by Dr. John Treadwell Nichols on recognition marks 

 in certain species of birds, published in the preceding number of 

 'The Auk' ^ was read at the Philadelphia meeting of the iVmerican 

 Ornithologists' Union in November, 1911. The theory of recog- 

 nition marks was then unfavorably commented upon by several 

 speakers, of which the writer was one. He now^ wishes to put in 

 print a series of questions, which must be satisfactorily answered 

 by those who believe in the great importance of directive markings 

 if they would persuade others to share this belief. A statement 

 of the general theory ^ of recognition marks will be useful and to 



» Vol. XXIX, No. 1, Jan., 1912, pp. 44-48. 



2 It should be noted that this theory covers both "banner marks and "sight 

 clues." H. C. Tracy in 1910 (Univ. of Calif. Publ. in Zoology. Vol. 6. No. 13, 

 Dec. 28, 1910) separated these classes of markings, discrediting the. crude inter- 

 pretation of the former, but claiming utility for the latter. 



