Ornithological Observations in Shetland. 269 



followed, on the spur, by another three or four, and then 

 another and another, and thus they departed, in little batches, 

 till only about a dozen were left, who showed no desire to go 

 with the rest, but continued to stand or sit stolidly. Having 

 seen all I wished to see, therefore, I now pursued my path, 

 which lay through the place of resort, to the sea, where, how- 

 ever, I saw nothing worth entering. 



What, if any, conclusion, is to be drawn from the above 

 observations ? No cause beyond that of a common inclination 

 need be sought for to explain the quick following of one in- 

 dividual Gull by another (had this been the case) for probably, 

 taking the time of the day into consideration, each would 

 know or surmise where those that preceded it were off to, so 

 that a predisposition would be stimulated by example. But 

 why were the several departures in batches ? The same idea 

 seemed certainly, in each case, to occur to some of the birds 

 at the same time. If we liken each unit of the collected flock 

 to an electric battery dealing out shocks to other units round 

 about it, then both the force of the shock and the numbers by 

 whom it was felt would be in accordance with the strength of 

 the battery, that it is to say, in the case of thought transference, 

 with the vividness of the thought arising in the mind of each 

 bird. Thus (and this might conceivably depend upon at- 

 mospheric conditions), on a day when the birds were feeling 

 great mental alacrity, we migyt expect to see the whole flock 

 act suddenly, all together, in a flash, as in some of the cases I 

 have recorded ; but when they were duller and more mopish, 

 the impulse, in whatever part of the assembly it originated, 

 would not be likely to extend so far out from the centre of 

 energy — from any individual, that is, to say, or to produce 

 action in all those to whom it did extend. The result of this 

 might well be that the flock, instead of going off all together, 

 would do so in little groups or batches as has been here recorded. 

 In this case, the last batch, or, rather, a small number of birds, 

 towards the end, would be left alone, and, partly as a result of 

 this, since there would be no others around them, to transmit 

 the influence, and partly, perhaps, also, on account of fewness 

 of numbers being in itself, a less favourable condition for 

 thought-transference than the opposite one of a large assem- 

 blage, these might either stay longer before the </>i?P7 broke 

 out amongst them, or go at last upon individual prompting, 

 merely, without its having done so. I regret now that I did 

 not continue to watch till the birds were all gone, for I might 

 then have been able to judge of this. 



We have received the Report of the Norwich Castle Museum Committee 

 for 19 1 6, which gives the usual evidence of the good work done at this 

 institituon, with a list of the additions during the year. 



1917 Aug. 1. 



