396 THE THRUSH FAMILY 



It is possible that this clucking or tchucking note is a primitive 

 one common to the whole genus ; it is, as far as my observation 

 goes, the first to be used by fledgling thrushes and blackbirds in 

 addition to their call-note ptreep or ptrik ! Whether it also is 

 used as a call-note I am not certain. Adult blackbirds and thrushes 

 have, indeed, little occasion to use call-notes, except on migration, 

 as they are not gregarious. The migrating call-note of the song- 

 thrush is, according to Naumann, zipp ! 



The ptick ! and mink ! have probably similar corresponding 

 sounds in the language of the other species of the genus, but not 

 enough is known at present to justify any attempt to draw a 

 comparison. 



The blackbird differs from the song-thrush in the possession of 

 its very remarkable alarm rattle, which it utters generally when 

 disturbed into flight, reserving the mink ! and tchuck f for occasions 

 when it is engaged in keeping watch on the movements of an enemy, 

 cat, dog, or other. The typical rattle consists of the tchuck ! and 

 the high pitched wed! to which reference has already been made. 

 These are uttered in a variety of combinations, the most usual 

 perhaps being : Tchuck ! tchuck f tchuck ! tchuck / to-weet-a-weet ! to- 

 weet-a-weet! tchuck! tchuck! It is into the middle sounds that the 

 bird puts that tone of almost frenzied alarm, which appears to give 

 him a satisfaction that certainly is not always shared by his human 

 hearers, especially if they happen to be bent on observation or 

 slaughter, and therefore anxious not to arouse the suspicions of 

 the furred or feathered folk. 



Into the rattle there doubtless occasionally enter other notes, 

 but these are probably for the most part imitated from different 

 species. Both the blackbird and the thrush are good mimics. I 

 have heard the former, when following up the movements of a cat on 

 the prowl, add to its tchuck! the long-drawn plaintive alarm-note of 

 the robin. The thrush is said to introduce imitated notes into its 

 song. 



