THE COLUMBINE, OR PIGEON GROUP. 115 



are hatched blind, unfledged, naked, and help- 

 less, and require the assiduous care of their 

 parents, even for some time after they are able 

 to leave the nest. Consequently they are fed 

 by the parents, and herewith is connected one 

 of the most singular points in the economy of 

 these birds, which indicates their far remove 

 from any of the gallinaceous order. 



Most persons have had an opportunity of 

 seeing pigeons feeding their young ; the old 

 birds place their beaks in the open mouth of 

 the young, and by means of a voluntary action 

 transfer nutriment from their own crop into 

 that of their nestlings. Many naturalists have 

 supposed the nutriment thus transferred to 

 be nothing more than the macerated grain, or 

 peas which have been previously swallowed ; 

 but this is not correct ; for at first the young 

 are not capable of digesting this coarse aliment. 

 They are, in fact, fed by a secretion closely 

 analogous to milk, and poured out from cer- 

 tain glands in the crop, both of the male and 

 female, but at the time only when such a 

 secretion is needed. This fact was correctly 

 ascertained by the celebrated John Hunter. 

 " During incubation (he says) the coats of the 

 crop in the pigeon are gradually enlarged and 



