THE ROOK AND JACKDAW 45 



which also point to the carrion-crow as the chief offender. It may be 

 added that they explain almost every desertion of a rookery about the 

 cause of which we possess unquestionable evidence. They probably 

 explain desertions attributed to other causes, more or less fanciful, 

 such, for instance, as the popular superstition that makes the sudden 

 desertion of the rookery a sure sign of coming calamity to its owner. 

 It is only fair to add that the rooks themselves have been known to 

 mete out to herons the treatment they suffer at the beaks of their own 



congeners. 1 



Crow incursions apart, rooks are very difficult to expel from a 

 rookery, as those know who have tried. One method that is adopted 

 in the Black Forest and parts of Switzerland is sufficiently curious to 

 merit notice. AVisps of long straw, each containing as much as one can 

 grasp in the hand, are hung by hooks to the branches of the nesting 

 trees, and there allowed to swing in the breeze. The device was tried 

 in the Zoological Garden at Frankfurt. The rooks at once left, and 

 did not reappear. Later a single pair built near the Garden. The 

 wisps again entered upon the scene, and the pair, after going and 

 returning twice, took a last long look from a neighbouring tree at the 

 uncanny yellow things that were sometimes so suspiciously still, and 

 at other times so alarmingly and fantastically energetic, uttered a 

 melancholy croak, and vanished for ever. 



The busiest time in the rookery comes when the eggs hatch, both 

 parents then straining every nerve to cope with the insatiable 

 appetites of their rapidly growing offspring. It has been stated that 

 at first the actual distribution of the food to the young is done by 

 the mother only. She takes it " from the father, passing it on doubly 



1 I find that in his Ornithologische Fragmente, p. 150, Petenyi records one case of ravens 

 being driven away by the united efforts of rooks. The following cases of the desertion of 

 rookeries caused by carrion-crows are recorded in the Field they include one by a hooded- 

 crow : 1864, xxiii. 291 ; 1872, xxxix. 211, 234 (three cases) ; 1875, xlv. 420, 464 (five cases) ; 1884, lix. 

 534, 580, 702 (three cases) ; 1888, Ixxi. 654 ; 1891, Ixxvii. 539, 631, 641 (three cases) ; 1892, Ixxix. 545, 

 625 (two cases) ; 1893, Ixxxi. 470 ; 1899, Ap. 8. A case is also cited by W. Ward Fowler in the 

 Zoologist, 1896, p. 145. For incursions by ravens see Montagu, Dictionary of Birds, and 

 W. Borrer, Birds of Siissex, p. 74. For two instances of rooks dislodging herons, see J. A. 

 Harvie-Browu and H. A. Macpherson, Fauna of the N.-W. Highlands and Skye, 1904, and 

 F. C. R. Jourdaiu, Victoria History of Derby, vol. i. p. 13. 



