26o BIRDS 



It lacks the length and slimness of its relatives, but excels 

 in crop properties. The Cropper is noted for its merry 

 nature, and is rapidly gaining followers in this country. 



The Performing Tumblers 



The Tumblers and their derivatives fall naturally into two 

 groups : those which are bred for their flying or performing 

 qualities and those which have lost these characters and are 

 kept for exhibition purposes only. Since the former natu- 

 rally preceded the others, we may consider them first. 



The action of the Tumbler is well known to nearly every 

 one. In its simplest form it is a single backward somer- 

 sault, made in flight, and from which the bird recovers 

 gracefully. This may be increased to two or three turns 

 in the Common Tumbler, or a swift succession of four or 

 more in the Roller. " What makes the Tumbler tumble " 

 no doubt has been a moot point among breeders ever since 

 the first bird went over, and it has never been satisfactorily 

 settled. That it has a physiological cause, such as a defec- 

 tive inner ear or brain, there can be no doubt, but the prob- 

 lem is so clouded by what appear to be psychological ques- 

 tions that it will not easily be solved. At any rate, the 

 facts remain that the bird does go over, that he does it more 

 freely at certain times, as when flying with his mate, and 

 that under stress of necessity, when pursued by a hawk or 

 striving to regain his place in the kit, he flies as well as any 

 pigeon. On the other hand, some individuals, particularly 

 among Rollers, appear to lose entire control of themselves, 

 and having started to roll, continue until they strike some 

 object which stops their fall. Such birds, which are known 

 as " roll-downs " or " mad rollers," never regain the ability 

 to fly safely once they have lost it. 



The tumbling character responds to the usual laws of 



