IMIKHI I AM '];, FERTILITY, AND SEX IN PIGEONS. 



TABLE 118. 



cf oriental X risoria hyb. (1); 5/8/0 4; stolen 7/19/12; 8 + yr. (see pi. 13). 

 9 C. tabellaria (prob. 3 + yrs. old); color very pale, with two pale bars. 



Al. 5/2/07 hatched 1 color of homer alive 9/20/09 2.1 + yr. 



A 2. 5/4/07; no development. 



B. 2/7/08; no dcvel unit. 



"Birds laid many eggs here; no development, or just a suspicion of a beginning of development." 



li 1. 1'-' 1 I; no development. 



B 2. 12/16; no development. 



c'l. i 1:1 osi; no development. I) 1 . n ' 1 ; no development. E 1. 3/15; some development. 



C2. 1 17/09; no development. 1) 2. 3/3; no development. 10 2. 3/17; some development. 



F 1. May; no record. CJ 1. 6/15; developed a blood circle. 



I" 2. May: no record. G 2. 6/17; developed a blood circle. 



/I>one developed for 5 or 6 days; other punctured a hole in shell and died. 

 H 2. 7/oJ 



" I 1. 8/1 hatched 2 dead 4/17/12 32 mo. 



12. 8/3; "a trace of development but not enough to give an embryo." 



? J 1. 4/20/10; died 10/26/10. "I could find neither male nor female organs." 

 J 2. 4/22/10; no development. 



K 1. 6/4 ; no development. LI. 6/23; no development. Ml. 8/29; no development. 



K 2. 6/0; broken. L 2. 6/25; no development. M 2. 8/31 ; no development. (F 1) 



1 "This is not a really strong bird; he never spreads his tail in flight and shows, till now (9/20/09), no desire to mate." 



2 "The male parent is now 5 years old and is apparently at his best; the female is also (probably) about 5 years old." 



BLOND AND WHITE RINGS CROSSED WITH THE EUROPEAN TURTLE-DOVE AND ITS 



COMPLEX HYBRIDS. 



The formation of a scries of complex hybrids was begun by crossing a single 

 European turtle-dove (Turtur turtur) female (B 1) with an F2 alba-risoria hybrid. 

 The resulting offspring are thus trispecific and bigeneric hybrids. These hybrids 

 were back-crossed to each of the three parent species, and the resulting hybrids 

 were variously back-crossed and inbred; one Avas out-crossed with a fourth species, 

 St. humilis. That this extent of breeding was possible is evidence that these crosses 

 of species and genera 8 were more fertile than the two groups of crosses (involving 

 subfamily and family crosses) hitherto considered in this chapter. The high degree 

 of complexity of the hybrids and the inbreeding involved are, at the same time, 

 however, a guarantee of a restricted fertility and of a progeny not strong. The 

 records bring out both of these points. There is much infertility in all of the mat- 

 ings and in only a single case is an offspring known to have lived as long as the 

 individuals of the shortest-lived of the parent species normally live. 



Much of this crossing was done as a means of determining whether and to what 

 extent "characters are divisible. " The color data arc tabulated, therefore, in many 

 cases as fully as they were recorded. A discussion of the data on the divisibility 

 of characters is separately given in Chapter XVII, and only the data on fertility 

 and sex, together with a proper identification of the crosses, require treatment here. 

 These three latter topics will be considered together. 



A turtle-dove female was crossed with an alba-risoria x risoria-alba male, and, from 

 this pair 7 of 12 tested eggs hatched (table 119). Three of the sons (cTD 1, c?G, and 

 dV 1} and one daughter (D 2) were mated back to ring-doves; two sons and the 

 daught cr with blond and white ring-doves. It will be noted that in the first cross color 

 is sex-limited in its inheritance. The males are darker than the females, the dam is 

 darker than the sire. This same association of sex and color seems also to obtain 

 when this same turtle-dove was mated (table 120) to a grandson (through St. risoria). 



1 The proper basis for a comparison of the generic and subfamily crosses was noted at the beginning of this chapter. 

 KDITOR. 



