58 A. H. Hamer 



tion of pleasure is often unmistakable. In my own view the 

 " chattering " type of song is simply a stimulus and expression of 

 joy and the proclamatory type has been developed for the 

 special purpose of territorial warning. It is chiefly characteristic 

 of soberly coloured territorial birds in situations where conspicuous 

 colouring would be out of accord with the surroundings. In 3eed 

 eaters the song no doubt is both an expression of pleasure and a 

 serviceable adjunct of what I have called " limited " territorial- 

 ism, i.e. care of the nest and perhaps immediate surroundings. 

 Birds in an aviary are certainly very prone to pull each other's 

 nests to pieces for the sake of the material, and it is clear that 

 among birds of the same species the temptation to rob must be 

 great. 



Examples of other devices for territorial warning such as the 

 bird flying over its preserve shaking long plumes or clapping its 

 wmgs will occur to everybody. My suggestion is that all these 

 things have been developed by natural selection for that purpose, 

 and not by sexual selection. 



(A) As, for instance the cock ostrich which " rolls from side to 

 side with wings outspread, then stalks majestically as if he 

 meant business." (F.H.H.) 1. 

 (.B) and *'so are the white ynngs of the ostrich which he often 

 waves about whilst parading round his territorial ground 

 that onlookers in adjacent camps may have a care.'* 

 (F.H.H.). 

 (C) In this connection the observation by Mr. Arthur Reid in 

 this Journal (Vol. II. No. 2, pp. 261-263) is interesting. 

 Speaking of the spawning of the brown trout he says: 

 " During these days the fish jealously guard their de- 

 posit, the cock fish chasing away any other that may be 

 approaching his preserve." Again, speaking of the rain- 

 bow trout, **the beautiful red lateral rays increase in bril- 

 liancy as the spawning season approaches." 



^Mr. Fred Holland of Despatch who has kindly given me some 

 useful notes, particularly his first-hand observations of the 

 ostrich. 



