WINTER ROOSTING COLONIES OF CROWS. 341 



It is an interesting, although rather discouraging, operation 

 to attempt to separate the variously intoned " caws" and imagine 

 the condition of mind each one represents. It is a veritable 

 Babel ! Old Crows, with a voice like the rasp of a file as it plays 

 on the edge of a saw ; middle-aged Crows, with long-drawn 

 "caws" that have andante movements about them, destined to 

 linger in one's ears after the musical apparatus has vanished 

 from sight; and young Crows, just learning the difficult art of 

 expressing their emotions, who get along excellently until, all of 

 a sudden, their note terminates in something totally unexpected, 

 like a boy at the adolescent age, when he is never certain whether 

 he will talk falsetto or bass. But in all these different shades of 

 tone there is that one unmistakable nasal basis which so clearly 

 distinguishes the Crow's "caw" from all other bird-notes. 



C. C. Abbott says : " Crows have twenty-seven distinct cries, 

 calls, or utterances, each readily distinguishable from the other, 

 and each having an unmistakable connection with a certain class 

 of actions ; some of which, as for instance the many different 

 notes of the brooding birds, are only heard at certain seasons." 

 Though we may not agree with such an exact classification, yet 

 it is undoubtedly true that Crows express quite different states of 

 mind by quite different notes. 



A determination of the exact number of Crows here collected 

 is not possible, but even the most sober observers place it among 

 the hundreds of thousands. As a basis for an approximate calcu- 

 lation, I have made the following observations at the roost : — 



With the aid of two friends, fifteen different square rods, 

 taken here and there at random, were paced off, and the number 

 of trees thereon capable of furnishing roosting tops counted. 

 An average gave us nine and three-fifths trees per square rod. 

 At any one roosting the Crows occupy about ten acres, or 

 (160 x 9f X 10) = 15,360 trees. If on each tree fifteen Crows 

 roosted — and that, if anything, is not too large an average — we 

 should have 230,400 Crows in the colony.* Because of the dim light 

 at sunset, my attempts at taking instantaneous photographs of the 

 incoming streams of Crows were failures. A view, however, of 



* It is difficult to realise the meaning of such a large number, and 

 perhaps an illustration may help us. It happens that if one Crow came in 

 each second, day and night, it would require just sixty-four hours for this 

 number to assemble. 



