170 INHERITANCE, FERTILITY, AND SEX IN PIGEONS. 



Streptopelia risoria. — ^Attention may first be given to features of the record 

 (tables 174 to 176) other than sex and fertiUty. In these tables" data are given for 

 the time consumed between sets or clutches of eggs in the blond ring-doves. This 

 period is variable; but it is clear that in the season which was later found to be that 

 of "weak germs" there is probably no natural tendency to shorten the period. Such 

 a shortening of the period would of course tend toward still further "overwork," 

 which has been found to lead to the weakening of the germ. Rather do the data 

 indicate that in this late autumn and winter period, when the germs are weakest, 

 the birds are reproductively less active; and this corresponds thoroughly with the 

 common experience with doves and pigeons generally." 



The interval between the laying of the 2 eggs of the clutch and the period of 

 incubation were in many cases very accurately determined. The period for the 

 former is nearly 40 hours; for the latter the period is variable and is different for the 

 2 eggs of the clutch, the first egg requiring usually 12 to 24 hours longer than the 

 second. The author has pointed out, however, that the first egg is usually not 

 incubated perfectly during the first 12 to 24 hours; the female sits or stands but 



Table 169. 

 cT Sp. suratensis (1); from dealer (9/30/07); (said to have come from Borneo); alive 1915. 

 9 Sp. suratensis (1) ; from dealer (9/30/07); dead 1/12/09; 2+ yr. 



A 1. 10/14/07\ , , , J , . 1 .u I 1 J PI- 6/30; deserted. 



A 2. 10/16/07}""'^ ^^'^"=^<=^' neglected; other failed. p .-, /^^j deserted. 



B 1. 11/29; hatched; dead, cold. Q 1. 7/9; no record. 



B 2. 12/1; did not hatch. Q 2. 7/11; no record. 



_, , „,„^,„„ ,. . u 11 .1 t Rl.7/19 21 probably died early. 



S^ 2/25/08; thin shell; no development. ^ probably died early. 



C 2. 2/27; thin shell; no development. ' f j j 



^ ,„,.,, ^ ,,,,._ , SI. 7/27; did not hatch. 



^l-V,V ^, ' ! ' , ^\^.^f'- S 2. 7/29 23 probably died very early. 



D 2. 3/9; fully developed; failed. ' 



^, o,,;,,,,^ . ,, Tl.8/4 24 dead9/l4/08. 



5 ,V o^i^' " *^™ ''"u"'^'"' ""If cf T 2. 8/6 25 dead 9/10/08. 



; 2. 3/20; full term embryo; cold. 

 F 1. 3/29; no record. 

 F 2. 3/31; no record. 



Gl. 4/5 10 hatched. 



G 2. 4/7; dead at 3 days. 

 H 1. 4/13; failed. 

 H2. 4/15; failed. 



I 1. 4/22 11 hatched. 



I 2. 4/24; hatched; dead at 6 days. 



U 1. 8/14; developed; deserted. 

 U 2. 8/16; developed; deserted. 



VI. 8/22 26 hatched. 



cf V 2. 8/24 27 hatched; dead 9/19/14. 



W 1. 8/31; hatched; died, neglect. 

 W 2. 9/2; not hatched. 



XI. 9/7 28 hatched. 



X 2. 9/9; no development. 



Y 1. 9/15; failed. 



V2. 9/17; failed. 



Z 1, 10/3; AA 1, 10/11; BB 1, 10, 20, not incubated. 



Z 2, 10/5; AA 2, 10/13; BB 2, 10/22, not incubated. 



CC 1. 11/9 29 hatched; died 2/9/09. 



CC2. 11/11. ...30 hatched; died 2/10/09. 



DD 1. 11/19; no development; neglect (?). 

 DD 2. 11/21; no development; neglect (?). 

 EE 1. 11/28; hatched; not fed. 

 EE 2. 11/30; fully developed embryo. 

 Parents removed 12/1/08. 



(Sh 0/13) 



Note. — The second egg was less fertile, or produced a bird clearly less strong, in 7 cases; the first egg showed the same in 1 case. 



' These three tables were prepared in their complete and present form by the author. 



' " November 6, 1908. The pigeons have been doing less and less since August and arc now pretty near the lowest 

 ebb. I have only 2 pairs of common pigeons (out of 10 pairs) with eggs and 2 with young." (R 16) 



