HEREDITY loi 



thrush and in the American robin this note seems 

 to be abbreviated to a shorter and somewhat 

 harsh chirp ; this, however, in both species, is some- 

 times prolonged to a much greater resemblance to 

 the redwing's cry. In July and August young 

 blackbirds, when disturbed, often utter, as they fly 

 away, a short squeak or chirp somewhat plaintive in 

 tone, and exactly resembling, except in its briefer 

 length, the cry used by the bird when migrating in 

 late autumn. The young of the American robin, 

 which, from their colours and manners, would in 

 England be assuredly mistaken for young blackbirds, 

 utter, at the same season and age, precisely similar 

 sounds upon the like occasions. I have never known 

 a blackbird, when flying high and steadily to the 

 south-eastward (as do the redwings) over Gloucester- 

 shire in autumn, and apparently migrating, utter its 

 alarm-note, such as Herr Gatke records as uttered 

 by the blackbird when passing at night the light- 

 house at Heligoland. Probably near the lighthouse 

 a passing bird would utter its alarm. The note I 

 have heard from birds migrating has been a cry 

 closely like, but distinct from, that of the migrating 

 redwing. I have also heard this variation of the cry 

 at night. The blackbird sometimes utters it by day 

 in the same season, when entering a thicket. This 



