CHAPTER X11I 



OTHER PIGEON HYBRIDS AND THE BREEDING OF SEVERAL PURE 

 SPECIES OF DOVES AND PIGEONS. 



There remains for presentation the data for a few crosses of pigeons belonging, 

 for the most part, to groups not hitherto considered. It is also desirable to treat 

 here some data upon the breeding, apart from crossing, of pure wild forms (with 

 one exception). Excepting a relatively small amount of data upon hybridization 

 and simple breeding, which it is quite necessary to place in Volume I of these works, 

 all of the author's results in this field are included in this volume and concluded 

 in the present chapter. 1 



The materials now to be considered offer further evidence upon many of the 

 topics which have formed the centers of interest throughout the previous pages. 

 Such topics touched upon by these data may be enumerated: (1) the exclusively 

 male offspring of crosses of most widely separated species; (2) the lower percentages 

 of males from less widely separated crosses; (3) relatively large numbers of infertile 

 eggs from the wide crosses; (4) a restricted life-term for many or most of the em- 

 bryos and offspring of the widest crosses; (5) abnormally sexed individuals from 

 hybrid parents; (6) weaker germs from the end of the season; (7) a case of the 

 reversal of dominance of color at the end of the season; (8) the predominance of 

 males from the first egg of the clutch in crosses; and (9) also in some pure-bred 

 species. Some hitherto unconsidered data on the breeding of certain pure forms, 

 on the incubation period, on the time between the 2 eggs of the clutch, and between 

 different clutches, are also given in the second part of the chapter. 



SEVERAL CROSSES OF DOVE9. 



It is found convenient to treat 8 crosses or kinds of crosses separately. 



Senegalensis x alba. These two birds belong to different genera. Stigmato- 

 pelia senegalensis is a smaller dove than the blond and white rings with which it 

 was crossed. An adult male of this delicate and very distinct species is shown in 

 pi. 27. Two of three Senegal x blond matings proved fully fertile (table 157) ; the 

 pair that showed a limitation upon fertility produced all of its eggs in late summer. 

 The female offspring are notably smaller than the males; and this is apparently 

 true also when the blond ring is used as the female in the cross. 



A brother-and-sister mating of these hybrids was largely infertile (table 158), 

 though 3 other males of this fraternity were almost fully fertile when mated to 

 pure St. risoria (table 159) ; and a fourth male proved similarly fertile with Spil. 

 suralensis (table 164) . The mating with risoria yielded (pair 3) from the last egg of the 

 season an abnormally sexed individual. Pair 1 produced 12 eggs; 10 were tested and 

 all were hatched. The 6 eggs laid before July 5 all hatched birds of dark, risoria- 

 like color; the bird from the seventh egg (August 1) was "grayish, nearly white"; 

 its clutch-mate was "white"; the ninth egg (September 6) hatched "white"; the 



1 Numerous records of little consequence, of matings of very short duration, and data not full enough to have 

 significance have, of course, not been presented. All matings giving an adequate or significant test of complete 

 infertility have been specially listed in Chapter II. The textual statement of the present chapter was written by the 

 editor. 



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