The Molothrus Family. i6i 



had a right to expect it would receive, either from 

 Mr. Darwin or Mr. Romanes, as regards the Molo- 

 thrus, an American species alHed to our starlings, 

 which have parasitic habits like those of the cuckoo. 

 The Molothrus bonariensis lays so many eggs in alien 

 nests that it is hardly possible many of them can be 

 hatched. These birds have the extraordinary habit 

 of pecking holes in the eggs of the foster-parents to 

 ensure that their own young shall be reared — a habit 

 which some observations would lead us to believe our 

 cuckoos sometimes practise, if an egg of theirs is laid 

 in the nest of a bird whose young is large and might 

 be too strong for the young cuckoo to turn out. 

 Molothrus precins never lays more than one egg in a 

 foster-nest, so that the young bird is securely reared. 

 What a satisfaction it would have been to know how, 

 as to size, the eggs of the various families of Molo- 

 thrus stood to each other ; but men like Mr. Darwin 

 and Mr. Romanes, if they satisfy themselves about 

 important practical points like these, they certainly 

 do not manage to satisfy us very often, indeed. Per- 

 haps that is because we have dwelt too long on one 

 special and particular subject ; but that should only 

 gain for us from their followers something like sym- 

 pathy and appreciation. 



" By a continued process of this nature," says Mr. 

 Darwin, " I believe that the strange instinct of our 

 cuckoo has been formed." Yes, but as, according to 

 him, the American cuckoos remain, as regards this 

 habit, merely occasional and aberrant depositors of 

 eggs in other birds' nests, what is the element that in 

 our cuckoos determined their passage from this aber- 

 rancy even if we admit it — to definite, sustained. 



