238 Tlie World-Evidence. 



colour, but also in size. They show a pearly white, 

 often a pure white, or greyish white, or pale bluish 

 ground colour, and are often spotted, more or less 

 densely, with chocolate-brown, lavender and cinna- 

 mon-brown spots. * We have as yet, though we 

 have very diligently sought for it, met with no record 

 as regards the weight of these eggs as compared with 

 the eggs of other birds of the same size ; but, from 

 analogy, we should expect it to be comparatively 

 heavy, as is the case with our cuckoo's eggs. Dr. 

 Elliot Coues, one of the best authorities regarding 

 this bird, writes : 



" No a priori reason appears to me why the egg 

 should not have been of ordinary dimensions and a 

 different series of birds been called upon to incubate 

 it ; while, as the facts stand, it is clear that the 

 bigness of the egg in comparison with those among 

 which it is usually, deposited, and not its smallness 

 relative to the cow-bird's bulk is the favouring ele- 

 ment ; for the larger egg must mechanically obstruct 

 the incubation of the smaller eggs, and so receive 

 the greater share of warmth from the bird's body. . . 

 It is unusually small that it may be committed to the 

 charge of birds able to hatch it, yet too weak to eject 



it."t 



Mr. Hudson notes the great variety of eggs, but, 

 from observations, thinks that the eggs of the same 

 individual show a family likeness. 



The cowbird's eggs, like our cuckoo's, are thus 

 very small compared with the size of the bird. 



Major Bendire, in his most interesting monograph 



* Nehrling, ii, p. 245. 



■\ Birds of the North-West, p. 152. 



