BREWSTER'S WARBLER. 71 



4. Voorhees, Auk, 1894, 11, p. 259-260. Lawrencei 9 feeding first plumage 



[ ? I young, Jul}' 12, 1893, which appeared to be pinus; showed clearly the 

 well defined black lores of pi/i MS. [From the date and description, these 

 young were probably in first-autumn plumage.] 



5. Dwight, Sequence of Plumages, Ann. N. Y. Acad. Sci., 1900, 13, p. 246. 



Englewood, N. J. Pinus feeding two young, one of which is pinus, the 

 other lawrencei, June 28, 1897. 



In dealing with the observations pertaining to the first category one is 

 seriously embarrassed in many cases by the insufficiency of the evidence adduced 

 to show that the birds observed were mated. In some cases, indeed, the ob- 

 server has failed to give any facts whatever to estabUsh the conjugal relation, 

 whatever good evidences he maj' have had and withheld from publication. 

 This is very regrettable in a matter of so much interest. To one who has perused 

 the foregoing pages it will be clear that the mere association at a certain time of a 

 male and a female is not enough to prove that they are paired. In the lack of a 

 protracted series of observations the evidence of conjugal union obtained by 

 seeing the male feed the female, or the male and female feed the young will be 

 accepted by every one who is familiar with the life of these birds as conclusive, 

 — as conclusive, in my estimation, as the witnessing of coitus. 



Application of rigid tests will show that probably not more than one half 

 of the eighteen recorded cases, given on page 68-70, are certain. The others 

 must be regarded as probable, some of them, in fact, as merely possible. All 

 of the records may be summarized as follows : — 



Pinus Xchnjsoptera. cfX9,2; 9Xcf, 1; = 3. 



Pinus Xlawrencei -\- chnjsoptera. d' X 9 , 1. 



Pinus Xlawrencei. 9 X cf , 2. 



Pinus Xleucobronchialis. cfX9,2;9Xcf,3;=5. 



ChrysopteraXleucobronchialis. cfX9,4; 9Xcr,2;=6. 



Lawrencei xlawrencei (?), 1. 



It appears from the above summary that although eleven cases, more or 

 less well authenticated, of the mating of Brewster's Warbler have been observed, 

 yet in not a single instance has it been found matched with another Brewster's 

 Warbler.' The union was always with either a Blue-winged Warbler or with 



' No particulars concerning the Lawrence's Warbler found breeding near New Haven, Conn., 

 June 5, 1893 (A. H. Verrill, Auk, 1893, 10, p. 30.5) are given, so that we are left in the dark as to whether 

 this was a genuine case of a "hybrid" mated with a "hybrid." 



