1792 Thk Zoologist — August, 18G9. 



of plenty, and as yet no clew whatever has yet been found to their 

 recurrence. With this introduction, I will give Wilson's narrative 

 exactly as it stands. 



" The most important feature in the natural history of these birds 

 is their migration. These migrations are caused by the necessity of 

 providing for food, and, consequently, they do not take place at any 

 fixed period or season of the year; indeed, it happens sometimes that 

 an abundant supply of food in one district will keep these birds absent 

 from another for years. The multitudes of these birds almost pass 

 belief. In the autumn of 1813 Audubon left his home at Henderson, 

 on the banks of the Ohio, on his way to Louisville : having met the 

 pigeons flying from N.E. to S.W. in greater numbers than usual, he 

 felt an inclination to enumerate the flocks that would pass within the 

 reach of the eye in the course of one hour. He dismounted, and seat- 

 ing himself on a small eminence, began to mark in his pocket-book a dot 

 for every flock which passed : finding, however, that this was scarcely 

 possible, and feeling unable to record the flocks as they constantly in- 

 creased, he rose, and counting the dots he had already put down, 

 found that 163 had been made in one minute. He travelled on, and 

 still met more the farther he went. The air was literally filled with 

 pigeons; the light of noon-day became dim, as during an eclipse. 

 Whilst waiting for dinner at the ' Sun,' Audubon saw at his leisure 

 immense legions still going by, and he says, ' But I cannot describe 

 to you the extreme beauty of their aiirial evolutions, when a hawk 

 chanced to press upon the rear of a flock. At once like a torrent, and 

 with a noise like thunder, they rushed into a compact mass, pressing 

 upon each other towards the centre. In these almost solid masses 

 they darted forward in undulating and angular lines, descended and 

 swept close over the earth with inconceivable velocity, mounted per- 

 pendicularly, so as to resemble a vast column, and when high were 

 seen wheeling and twisting within their continued lines, which then 

 resembled the coils of a gigantic serpent.' Before sunset Audubon 

 reached Louisville, distant from llardensburgh fifty-five miles; the 

 pigeons were still passing in undiminished numbers, and continued to 

 do so for three days in succession. 



" Audubon attempts to reckon the number of pigeons in one of 

 these flocks, and the daily quantity of food consumed by it. He takes, 

 as an example, a column of one mile in breadth, and supposes it pass- 

 ing over us without interruption for three hours, at the rate of one 

 mile per minute: this will give us a parallelogram of 180 miles by I, 



