THE GRAFTER 225 



the skin, crawl out of the cow's back, and drop on the 

 ground where they are transformed into the mature insect. 



Father taught me that cowbirds eat these grubs when 

 they crawl out of the cows' backs and so are a protection 

 to the cows. I am inclined to doubt this, for while those 

 birds lived with our cows for years, every spring the cows' 

 backs were full of the "warbles." If the birds had been 

 active in catching the grubs, they should have grown less 

 numerous from year to year. 



Finally I discovered something about these birds that 

 changed me from their friend to their untiring enemy, 

 and finally I exterminated them from our farm. 



Our peach orchard was a favorite nesting place for yel- 

 low warblers, vireos, and other small birds. One spring 

 a red-eyed vireo nested in my favorite peach tree. This 

 was a seedling that ripened its fruit very early and was 

 of exceptionally good quality. That spring I had fallen 

 into the habit of visiting the tree every two or three days 

 speculating how long it would be before I could get a 

 ripe peach. One day I discovered a vireo's nest there, con- 

 taining three eggs. 



The next day there were still three eggs in it, but they 

 were not all vireo eggs. One was much larger, and there 

 was a broken vireo egg on the ground underneath the nest. 

 I could not understand that, so I went back to the nest 

 the next day and found another vireo egg in it. Then 

 the vireo began sitting. Of course I was anxious to see 

 whether the big egg would hatch. It never occurred to 

 me that it was not a vireo's egg. Sometimes one of our 

 hens would lay an unusually large egg that contained two 

 yolks. Again one sometimes laid an egg not much larger 

 than a pigeon's egg, so it did not occur to me that this 



