HOW THE BIRDS KNOW 339 



make it sick to eat the caterpillar with the spines 

 on, then one grants to the bird the ability to think 

 and reason up to two separate perceptions on the 

 point. It hatf to think that the caterpillar would 

 be injurious if eaten whole, and then it had to think 

 out how to prepare it for food. One might reason 

 a degree further and say it had to recognize when 

 the spines were removed and the caterpillar suit- 

 able for food. Nor was it stress of hunger which 

 drove the bird to do an unusual thing, for it was 

 well fed at home, many of the neighbours fed it, 

 and it was regurgitating and hiding the food I 

 was giving it around the border of a pansy bed 

 when it espied the caterpillar. 



All I could make of it was that what I was of- 

 fering was unnatural food, and the bird would eat 

 it only in stress of hunger; the caterpillar was 

 nearer to its taste and though it was only a young 

 bird, raised in unnatural conditions, it knew how to 

 prepare the worm for its food. It would not do to 

 mention "instinct" in the case, because cater- 

 pillars are not a staple of crow diet. But there are 

 staple articles in the diet of every bird, things for 

 which they hunger; and they do not thrive if they 

 do not get them. 



Birds pay slight attention to a dog crossing the 

 woods and go beside themselves at the presence of a 

 cat, so beyond all question they know which animal 

 is dangerous to their welfare. It seems to be in 

 the blood of a falcon to love horses and dogs. You 



