SUPPRESSION OF SCENT 163 



people who have bred the species, recording that a 

 bird of his seemed never to leave the nest during 

 the whole time of sitting, so that chickweed growing 

 around grew all over its back. 



In any case birds need little food while sitting, 

 and their excreta are concentrated in a remarkable 

 way ; any one who keeps Fowls or Pigeons has 

 noticed that when a sitting hen leaves the nest 

 she voids a large mass all at once, and the scent 

 appears herein to be concentrated, thus explaining 

 the fact that the body-scent of a sitting game- 

 bird, so perceptible at other times to the nose of a 

 questing beast of prey, becomes suppressed, being 

 as it were driven inwards. 



In spite of the wearisome nature of the task as 

 it appears to u^, it is evident that birds must 

 experience great satisfaction in the action of 

 incubation, as also in the more toilsome but 

 seemingly more interesting process of rearing the 

 young, since they are so irresistibly impelled to it 

 that in many cases it is repeated several times 

 during the year ; in fact, some tame birds, such as 

 fancy Pigeons, Canaries, and Budgerigars, would 

 endanger their health and produce weakly offspring 

 by continually breeding in the case of the last 

 even in out- door aviaries in mid- winter if their 

 owners did not by removing nesting facilities, or 

 even by separating the sexes, put a stop to propaga- 

 tion after a reasonable number of broods had been 

 raised. 



Birds which have active young are less philo- 



