ORNITHOLOGICAL OBSERVATION IN ICELAND. 413 



action on the part of any two birds — for instance of these two 

 Swans, for they seemed to act exactly together, and to know, 

 together, exactly what they both meant to do.* 



The above remarks would apply more particularly, to the 

 origin of what may be called social antics, of movements, that 

 is to say, which do not apparently spring from any sexual 

 stimulus, but seem rather the outcome of some state of excite- 

 ment manifesting itself between two or more birds, which has 

 nothing to do with this. I do indeed think that various 

 antics which have become social have had a sexual origin, but 

 that is no reason why others should not have originated spon- 

 taneously out of social conditions. It is possible, however, that 

 in a wider and less specialised sense than that which I have 

 been considering, the ultimate origin of all social antics may 

 have been of a sexual nature. These Swans, for example, since 

 they were incubating, probably acted in the way they did, under 

 the influence of some kind of parental emotion, but the parental 

 instinct is born out of the conjugal one — follows it, at any rate, 

 by a fixed law of sequence — and though the very striking and 

 pronounced autumnal antics of the Stone Curlew seem to be of 

 a purely social character, yet the very fact of their manifesting 

 themselves at that season only (as far as I know) might incline 

 some to consider them as a sort of sequelae of the state of sexual 

 excitation belonging to the precedent breeding-time, which is but 

 just over. It is not, one may almost say, till the winter, that the 

 sex stimulus, in some shape or form, is quite dead, so that the 

 question whether social antics depend ultimately upon sexual 

 activity, in birds, could perhaps best be answered by an inquiry 

 as to whether, or to what extent, they also cease at that period. 

 Actions which do not stand in any relation to that factor ought 

 not, one would think, to be governed by the seasons in any way 

 which is at all correspondent to that in which it is. 



Some time before this Swan episode, one of the pair of Great 

 Northern Divers — that one probably that was on the nest when 



* This is perhaps suggested by the fact that only one of the pair turned 

 round, so as to front the one behind it. It would have been more in keeping 

 with what had gone before if this one had turned round too. Had it done 

 so, however, there would have been no confrontation scene, which seems 

 thus to have been desired by both. 



