THE WOMBAT. 41 



swallow anything it found as soon as possible, since it would thus 

 have more chance ot eluding the gull's observation, though this, I 

 believe, it hardly ever does. On the other hand it is possible 

 that the gull's approach — commencing from the first indication of 

 success on the part of its quarry — may be so swift that the latter 

 has rarely time to swallow on the ground, and finds it difficult to 

 do so during flight. It, when the peewit had once swallowed, it 

 could not be made to disgorge, we could better understand that 

 curious change of intention which the gull sometimes exhibits in 

 the very midst of flying down upon it. The precise manner, 

 therefore, in which the peewit is robbed may be as open to doubt as 

 it is in some other cases where the main fact is not less certain. 



A more interesting point is involved in the question of what is the 

 precise mental attitude of thegull towards the peewit and vice versa. 

 It might be thought that hostility, pure and simple, was the only 

 possible one in such a case as this, or that, if the gull had acquired 

 a contempt for the peewit, the peewit, at any rate must look with 

 terror and resentment on the gull. But if this last is the case how 

 is it that the two birds may constantly be seen standing almost side 

 by side with apparent indifference, and that, until the actual chase 

 has begun, the peewit never seems at all afraid of its persecutor ? 

 On the other hand, the gull appears to me to have acquired an 

 instinct similar to th?,t which restrains a shepherd's dog from biting 

 the sheep and only allows him to drive and hustle them. Though 

 he pursues closely he does not actually attack and his very cries 

 seem to express complaint rather than anger, as though he were 

 demanding what the peewit, as well as himself, knew to be his due. 

 It is, at least, possible that this may really be the case. However 

 a habit of this kind may have commenced, when once the weaker 

 bird had come to be terrorised by the stronger one, the latter would 

 be likely — on the principle of " least action " — gradually to 

 accustom itself to threaten only, and the threat, in time would 

 be responded to more as an instinct than in fear of something that 

 had ceased. Thus to the gull the peewit might become by degrees 

 first a subject having duties, and at last a dutiful subject; whilst 

 the peewit would see in the gull not so much an oppressor as an 

 existing and necessary state of things — in fact an institution. This 

 curious result — to which our human experience offers no sort of 

 parallel — is perhaps the most interesting feature in a species of 

 parasitism which is, in itself, full of interest. 



