Means of Dispersal. 29 



peat-bogs that are within a mile of an Oak-tree. They 

 are common also in some places on the top of the escarp- 

 ment of the South Downs, half a mile from Oaks, and 300 

 or 400 feet above them. They are always associated with 

 empty acorn-husks, stabbed and torn in a peculiar way. 

 In October and November rooks feed in the Oak-trees, and 

 I have long felt convinced that they were mainly responsible 

 for the dispersal of acorns. On October 29th of 1895, in 

 the middle of an extensive field, bordered by an oak-copse 

 and scattered trees, I saw a flock of rooks feeding and 

 passing singly backwards and forwards to the Oaks. On 

 driving the birds away, and walking to the middle of the 

 field, I found hundreds of empty acorn-husks, and a 

 number of half-eaten pecked acorns. It was noticeable 

 that many of them were not shed acorns, but were accom- 

 panied by acorn-cups, the stalks of which had been bitten 

 to tear them off the tree. The reason for the selection of 

 acorns in cups is probably that they are easier to carry —a 

 shed acorn must be an awkwardly large and slippery thing 

 for a rook's beak, one with a stalk will be more convenient. 

 Several uninjured acorns were found, one, almost uninjured, 

 had been driven by a single peck deep into the soft soil of 

 a mole-hill. 



In this way oak-woods must spread rapidly ; but we 

 still want observations as to the extreme distance to which 

 acorns are thus carried. I have seen seedling Oaks at a 

 distance of a mile from the nearest tree (not necessarily the 

 tree from which the acorn came) and have found the 

 characteristically torn husks somewhat further away.* 

 Mr. J. J. Armistead, moreover, recordsf that he once 

 found a young Oak in a sheltered ravine among sea-cliffs 

 on the northern coast of Hoy, Orkney. The tree was 



* Nature, No. 1358, vol. liii., p. 6 (1895). 

 t Zoologist, p. 19 ( 1 891). 



