CUCKOW. 399 



To what cause we may attribute the parasitism of the 

 Cuckow is at present beyond our knowledge ; and, when so 

 many other cases of the same habit throughout the whole range 

 of Natural History are remembered cases in comparison 

 with which that of this bird, though presenting some peculiar 

 characters, is by no means remarkable it would be vain, as 

 premised, to indulge in conjectures on the subject. Yet a 

 few of the explanations which have been proposed require 

 notice here, if only to shew their futility. First is that of 

 Herissant (Mem. de 1'Acad. R. des Sci. 1752, pp. 417-423, 

 pis. 15-17) who supposed that Cuckows do not hatch their 

 own eggs because their stomach lies behind the sternum and 

 beneath the bowels, forming a protuberance which would 

 make incubation inconvenient. This suggestion, which 

 found favour with Dr. Opel (Journ. fur Orn. 1858, pp. 205, 

 285) was, however, long ago shewn by White, in his 

 thirtieth letter to Barrington, to be insufficient, since a 

 Nightjar, which unquestionably broods its eggs, has a 

 similar arrangement of the viscera a fact that has since 

 been observed in many other birds that incubate. Prof. 

 Schlegel, in 1831, arrived at the conclusion that the peculiar 

 nature and effect of the Cuckow's food produces an en- 

 largement of the stomach, and at the same time affords but 

 little nutriment, whence follows a constant hunger, which, 

 he thought, influences the development of the eggs in the 

 ovary ; while the bird, incessantly occupied in search of sus- 

 tenance, has no time for incubation, and would have still 

 less the means of provisioning its young if it had to feed 

 them. Moreover the eggs being produced but slowly, and at 

 comparatively long intervals, the earliest of them would be 

 spoilt before the last was laid, and finally the young would 

 not be in a sufficiently advanced condition to perform their 

 migration.* These allegations have been disposed of by 

 Macgillivray (Brit. B. iii. pp. 123, 124), who found that the 

 stomach of the two common North-American Cuckows was 



* Prof. Schlegel's views have been adopted by some of the latest biographers 

 of this species, Dr. Altum (Journ. f. Orn. 1866, pp. 165-171) and M. 0. dee 

 Murs in his work ' La Verite sur le Coucou ' (Paris : 1879). 



VOL. II. 3 F 



