364 NOTES 



the water pans or submerged. This habit of course, is also 

 commonly seen in ducklings of other wild species, such as Pin- 

 tails (Dafila acuta). 



The one-fourth A. tristis hybrid ducklings were at first very 

 wild, far wilder than the pure wild Mallards, but they changed 

 with age and became much more like ordinary ducks. They 

 did not show any special aversion to taking food off the ground. 



In the wild state Anas tristis and Anas boschas are very sim- 

 ilar in habits and commonly intermingle, Anas tristis being 

 more of a coastal bird and having a different breeding area. 

 The different actions of the young under confinement is very 

 interesting, showing in the one bird an adaptability little short 

 of marvellous, and in the other closely related species a con- 

 dition that would wholly prevent domestication and almost 

 prevent breeding in the pure state. I may say that the female 

 of A. tristis very rarely lays eggs in capitivity, though the male 

 crosses quite readily with other species. A control in the be- 

 havior of the pure wild Mallards was obtained by a number of 

 young hatched by these same mothers in a secluded inclosed 

 pond. These young are as wild as any wild ducks in the open, 

 and it is rarely that one is able to get even a glimpse of them. 

 Their wildness then is immediately modifiable in the rearing yard. 



Behavior such as is carried by A. tristis certainly seems to 

 be of a markedly dominant character and analagous to that 

 seen in half bred wild rats and hybrid mice between wild and 

 tame stocks. 



Whether there is any tendency to a segregation of traits of 

 this sort remains to be studied, but to the writer it does not 

 seem as if this work would be at all easy or satisfactory to carry 

 out among ducks. 



SINGING MICE 



CHARLES A. COBURN 



The Harvard Psychological Laboratory 



In the literature of animal behavior appear several references 

 to the production by mice of sounds of musical quality. 



The "singing" of mice is described variously by different 

 writers. Lee ' states that it consists of a series of chirps at 

 the rate of three or four per second. At the beginning of the 



1 Lee, Henry. Singing Mice. Popular Science Monthly, 1878, Vol. 14, pp. 102-105. 



