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110 NATURAL SELECTION vexperiment to illustrate the question at issue has becomeavailable. Mr. B. T. Lowne, F.E.C.S., had three of the smallring-doves (Turtur risoria) which had been hatched in thebreeding box of an ordinary dove's cage. They were kept atfirst in a similar cage, with some hay, on which the twohen birds laid eggs and hatched some young. In the followingApril these birds were put into an aviary in the open air,in which was a large branch of a tree with numerous twigsand buds, and there was also a breeding box with hay andstraw. Noticing that the older birds perched on the branchwith small pieces of stick in their bills, Mr. Lowne suppliedthem with a quantity of twigs and small sticks, and thevery curious and interesting result was that they built a neston the branch and laid their eggs in it. But this was noteffected without much difficulty, and only after they hadreceived assistance. They first seemed to try to fix the twigsagainst the wall of the aviary or its roof, and waved themabout above their heads tillthey dropped them. Mr. Lownethen fixed some perches for them lower down, and wove somesmall branches together to afford an additional resting-place.They took possession of this and again carried up twigs anddropped them, and Mr. Lowne then observed that while thestraight smooth twigs fell to the ground those that were forkedoften lodged in the branches. He therefore supplied them withplenty of forked or branched twigs, and by carrying these upand dropping them (and I presume standing on them, or otherwiserendering them compact, though this is not mentioned)they at length (in three days) formed a nest " exactly likethat of a wood-pigeon." This " they lined neatly with straw,"and each dove laid two eggs in it. 1This experiment, though very interesting, isby no meanssatisfactory or conclusive. In the first place, pigeons are thevery rudest of nest-builders, and will sometimes lay their eggson a dense flatbough without any nest at all. Then it is clearthat these birds had no notion how to begin to build ; theyrequired to be assisted, and, as Mr. Lowne " says, as soon asa few branches had lodged below them, they finished the nestwhich accident had commenced for them." Then they lined it withstraw, which is not their habit in a state of nature, but appears1 Popular Science Revieic, New Series, vol. iii. p. 274.