342 THE ZOOLOGIST. 



one of the gathering flocks, taken about an hour before sunset, 

 as it flew by in a straggling stream, shows two hundred and 

 seventy-three Crows in the photographic field. On this basis, 

 the flying time (an average of a number of observations) for the 

 bird to cross the field being fifteen seconds, in three streams 

 coming in for one hour, we should have 199,560 Crows. But the 

 streams toward the middle and end of the incoming are manifestly 

 much larger than the above, so this number may be taken as a 

 minimum estimate. 



Dr. Godman says : " During hard winters many Crows perish, 

 and when starved severely, the poor wretches will swallow bits of 

 leather, rope, rags — in short, anything that appears to promise 

 the slightest relief." I have often found Crows sick of various 

 disorders which I shall not attempt to classify, going blind 

 and starving, and in the aggregate for a winter many suffer the 

 inevitable fate of mortals. I have found as many as eleven sick 

 and recently dead Crows upon the roosting-ground in one day, 

 and no doubt the Hawks and Opossums have found as many, for 

 they are so boldly fond of the birds as to become noticeably 

 increased in numbers in the region of the .roost in winter, and of 

 their visits well-picked bones scattered about bear testimony. 

 But the consumers of Crows are not confined to Hawks and 

 Opossums, for there is an old coloured man in the neighbourhood 

 who eats the fresh birds, and when his larder is abundantly 

 supplied, salts down the Crows for future use. 



Having the total population of the colony and the average 

 death-rate we may calculate the average age of the Crow. I think 

 that a death-rate of five for each night at the roost, drawn as an 

 average from a number of observations, is certainly not too low. 

 Allowing that during the almost equal period the colony is away 

 from the roost the same number die, we then have a daily death- 

 rate of ten, or a yearly mortality of 3650 Crows. So a colony of 

 230,400 individuals would be a fraction under eighty years in 

 dying off; or, in other words, the potential longevity of the Crow 

 would equal about eighty years. It is well known,* at least 



* "This bird sometimes lives for a century or more. Those have been 

 seen in several cities of France which have attained this age, and in all 

 countries, and in all times, it has passed as very long-lived." — Buffon, 

 ' Histoire Naturelle,' torn, xviii., 1775, p. 32. " The Raven likewise is 



