96 ORTHOGENETIC EVOLUTION IN PIGEONS. 



In a review of my paper, "The Problem of the Origin of Species," Dr. A. G. 

 Butler comments 44 as follows on my conclusion that the bars in pigeons have been 

 evolved from chequers: 



This is certainly not the conclusion to which a study of the nestling plumage of some 

 at least of the African doves leads me, inasmuch as the conspicuous spots on the scapulars 

 and inner secondaries appear in the adults with the disappearance of the juvenile bars. 



I presume that the maiden-dove (Calopelia puetta) , recently described by Dr. 

 Butler, 45 was one of the "African doves" he had in mind. This species is pictured 

 as having only three "metallic spots on the inner greater wing-coverts and largest 

 scapulars." An immature bird described by Captain Shelley in 1883 (Ibis, p. 322) 

 is referred to as having "black bars on the scapulars, wing-coverts, and secondaries." 



These "black bars" of the young are not further described, and I am therefore 

 in doubt as to whether they represent rows of cheqxiers or the higher stage of develop- 

 ment seen in apical crescents, a form characteristic of the inca-dove and the geopelias. 



The mature color-pattern in Calopelia does not differ widely in essentials from 

 those seen in some American species, e.g., the mourning-dove (Zenaidura caro- 

 linensis) and the zenaida-dove (Zenaida amabilis) . In the young of these doves we 

 find many typical chequers, more or less evenly distributed over the whole wing; 

 in the adult we have only a few of these spots left, and left in the same region in 

 which the three spots of the maiden-dove are located. The obliteration of the spots 

 in the American birds has, however, not yet been carried quite so far as in the 

 African dove. In the mature mourning-dove we find not only a larger number of 

 visible spots, but also many concealed vestigial spots. Zenaida has carried the 

 reduction of spots somewhat farther, and stands only a little behind the maiden- 

 dove. Our white-winged pigeon {Mclopelia leucoptera) has practically completed 

 the deletion of spots, only a very few vestigial traces being discoverable in a single 

 specimen obtained from Jamaica. I do not find such vestiges in white-wings from 

 Mexico and Arizona. 



In a male cape-dove (CEna capensis) that has just come to hand I find indica- 

 tions of a still closer correspondence to the Zenaida and Zenaidura types. In this 

 dove (pi. 42, fig. A) there arc two very short bars, one on the tertials (with one spot 

 on the right wing and two on the left), and another on the inner long coverts (with 

 three spots on the right wing and four on the left). These black ("steel-blue") 

 spots are subtcrminal squarish blocks on the outer webs. On the inner webs of 

 the tertials bearing the bar-spots I find elongate black spots reduced to narrow 

 marginal streaks in most cases. A tertial with such a streak on the inner web 

 extending nearly to its tip and a bar-spot on its outer web at a considerable distance 

 from the tip presents a picture quite characteristic of the zcnaidas and the mourning- 

 doves. 



So close and peculiar a parallel in the mature patterns of these doves would lead 

 us to expect fully as close a resemblance in the juvenal patterns; but Salvadori's 

 description of the young cape-dove does not seem to confirm this anticipation. 

 "The wing-coverts," as he reports, "are grayish-brown with blackish bands and 

 whitish-buff apical spots." 



44 Avicultural Magazine, Dec. 1906, p. 71. « Ibid., June 1900, p. 251 



