314 THE ZOOLOGIST. 



substituted Wood Pigeons for Babbits, and the ' vermin birds ' 

 once more fell victims." * It is not related how long this bait 

 sufficed. Eimer relates that, requiring Sparrows for the zooto- 

 mical studies of his students, he procured a new and ingeniously 

 constructed trap. " The result of the use of my trap was 

 surprising; almost immediately quite a dozen Sparrows were 

 caught in it. These were brought away as carefully as possible, 

 so that none were taken out in sight of their companions. The 

 trap was again set, and this time nine Sparrows were caught 

 equally quickly. I was very pleased with the invention, for it 

 seemed likely to put an end for the future to all my difficulties. 

 But it was to be otherwise. I noticed already that all the 

 Sparrows caught were young birds, hatched the same spring, and 

 therefore of little experience. Not a single old Sparrow had 

 entered the trap. And when I set it for the third time, not one 

 Sparrow went into it — it stood for week after week ; the yard was 

 full of Sparrows, but I caught no more. However, I looked 

 forward confidently to the next year — then I thought, young 

 Sparrows will get caught again ; and about two dozen would have 

 been enough material for my purpose. But I had reckoned 

 without the intelligence of the Sparrows. When I got out the 

 trap again next year, and had it set, not a Sparrow went into it. 

 But a curious spectacle was observed : apparently several Spar- 

 rows had the desire and the intention to go into the trap, and 

 these were obviously the young inexperienced birds which had 

 been hatched since the trap was last set ; but others, of course 

 the older birds who had learnt the danger of the wire-basket 

 from the loss of their families, kept them back by constant 

 earnest warnings, for the males, as soon as one of the yellow 

 beaks approached the cage, uttered their warning cry most loudly, 

 the cry which they always make when danger is present, and 

 which consists in a long shrill rattling * r-r-r-r-r.' "t It is well 

 known to poachers that when once a Hare has been netted, there 

 is no chance of its being taken again in like manner. Racher 

 than go through a second time, even though a " lurcher " be 

 but a yard behind, it will either " buck " the gate, or take the 



* ' Curiosities of Nat. Hist.,' pop. edit., 2nd ser. pp. 97-8. 

 f Eimer, ■ Organic Evolution,' Eng. Transl., pp. 235-6. 



