INSTINCT AND INTELLIGENCE IN BIRDS 123 



isolated facts, and too often falls into temptation by trying to interpret 

 them without a full knowledge of their history. The act in question 

 may appear irretrievably stupid or exceptionally intelligent, while upon 

 fuller knowledge, either view might prove wholly erroneous. Illustra- 

 tions could be multiplied, but the few which follow, may be of interest. 



Shrike Impaling Prey. — The great northern shrike is well known 

 to impale its prey, such as grasshoppers, small birds and rodents, on 

 thorns, and it presumably returns to them when in need of food, 

 although I am not aware that the bird has ever been actually seen in 

 the act of reclaiming its booty. According to some accounts the shrike 

 impales its prey in order to rend it with the greater ease, but still goes 

 on killing after it has satisfied its appetite. 



On April 8 of last year I happened to witness a futile attempt at 

 impalement under such favorable conditions of seeing all that tran- 

 spired, that any mistake as to the meaning of the actions would seem 

 to be impossible. A harsh piercing cry attracted my attention to the 

 bird, which almost at the same moment dived into the stubble of an 

 adjoining field, and came up with a large object in its bill. Fortu- 

 nately it flew directly towards me, and alighted on the bare, lower 

 branch of a maple tree, less than ten feet from my eye, as if completely 

 preoccupied, and indifferent to observation. I could now see plainly 

 that it held a little shrew, about three and a half inches long, and in a 

 strangle grasp by the nape of the neck, for the body was as limp as a 

 rag. The shrike at once proceeded to walk along the branch and try 

 to impale the rodent, extending its head and drawing the body of the 

 animal in a peculiar manner, against the soft twigs of the tree. It 

 tried the terminal twigs, and the equally soft lateral shoots, and went 

 through the same motions on two different branches. After several 

 minutes of this ineffective effort, with a loud rasping call of a different 

 character, it flew off in the direction of some woods, and was seen to 

 descend to the ground. 



The interpretation of such behavior seems obvious — that the shrike, 

 when under the spell of a strong impulse, does not know a thorn-bush 

 from a maple tree. Must it try tree after tree, until one of the right 

 sort is found ? If it can return to its tree by memory, why can not it 

 find one suited to its puposes by intelligence; or, was this a bird with 

 inherited instinct to impale, but with no previous experience with 

 thorns ? 



Bobin " Tying Knots." — So far as I have observed, the robin in 

 nest-building, ties no proper knots, unless the present case (Fig. 23) 

 be exceptional, although strings are coiled more or less effectively 

 about adjoining twigs. This nest was placed in a crotch of a pine tree, 

 and one of its supporting branches bore the peculiar double loop or 

 :< knot " which is here shown. It seems that a piece of string over two 



