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. Tllustra- 
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 ? ; 
Robin “ 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 
