RESULTS OF HYBRIDIZING RING-DOVES. 3OI 



the other. The white birds often show slight traces of melanin 

 pigment in their feathers, but this was also observed in presum- 

 ably pure stock as has been noted. The sex of ring-doves can 

 be determined satisfactorily only by breeding tests or by dissec- 

 tion. The sex of a number of individuals was not ascertained as 

 these died when there was no one on hand to make the necessary 

 dissection. Some nestlings have also been included, and their 

 sex was not determined. 



The total number of hybrids hatched was 151, and the sex 

 of 74 of these was ascertained. Of these, 32 were males and 42 

 were females. This preponderance of females is of no significance. 

 Table I. gives results of crosses between blond males and white 

 females. The ordinary Mendelian expectation is realized for color 

 here, as all of the offspring in Fi are essentially like one parent 

 in color, and the blond coloration is dominant. Whiteness of 

 plumage or absence of pigmentation is recessive to the presence 

 of pigment. Eight out of the ten birds of known sex were males. 



TABLE I. 



BLOND MALES X WHITE FEMALES. MATINGS i, 3, 4, 17, AND 23. 

 Fi 14 offspring all dark. 8 males, 2 females, 4 sex ?. 



Fl <B.<? B.9 



IB', 



W. 9 (Original Stock.) 



TABLE II. 



WHITE MALES X BLOND FEMALES. MATINGS 2, 5, 16, 26, 29, 30, AND 33. 

 Fi 18 blonds: 7 males, 3 females, and 8 sex?. 

 23 whites: 13 females and 10 sex ?. 



/B.d 1 B.9 W. 9 

 Fi < I. 



X- 



[w.cf B. 9 (Original Stock.) 



With the reciprocal cross as in Table II., about one half of the 

 offspring were white in FI, and all of the white birds whose sex 

 was ascertained were females. Again the dark hybrids were 

 mostly males. 



