ORIGIN OF TUMBLING IN PIGEONS. 129 



placed on the ground, when they roll over and over as if in a 

 fit, the natives stating that if not taken up they would continue 

 to do so until they died; though one of Mr. Tegetmeier's cor 

 respondents found that the only bird he allowed to go on 

 unchecked stopped itself at last from exhaustion. A sub- 

 variety of these birds is said to tumble, or rather roll, when 

 tapped on the head with the point of the finger. 



These facts open up a very interesting question as to the 

 origin of the tumbling propensity. Mr. Tegetmeier observes 

 that the various eccentric movements included in it " obviously 

 depend on an extra irritability of the nervous system," and 

 suggests a comparison that appears just between them and the 

 involuntary tremulous motion in the neck of a Fantail. Some 

 have maintained, on the other hand, that tumbling is voluntary 

 and the result of training, and a source of pleasure to the birds. 

 There is some reason for this view of the case in the fact that 

 a well-trained flight of birds will often go through their 

 performances in evident concert, and so close together that it 

 is almost impossible to conceive they would not come into 

 collision unless they had control over their movements-. It is 

 also noticed that when a bird has been away some miles from 

 home, on its return to its mate the pair will often go through a 

 regular performance, as if in joy at the re-union. So much also 

 depends upon judicious treatment and training, that it is 

 natural owners and breeders should attribute the performances 

 of their birds to this cause. 



In our opinion, the only tenable hypothesis is that' advanced 

 by Mr. Henry Kesteven, M.R.C.S.,* the evidence- for which, 

 may be shortly stated and is of unusual weight. This view 

 attributes tumbling to some form of epilepsy. On closely watch- 

 ing Tumblers, it is seen that the act of tumbling consists in a 

 violent spasm of the muscles of the back, which is bent into the 

 form of an arc, while the wings at the same time strike together 



* See Live Stock Journal, May 31st and August 30th, 1878. 

 J 



