16 BIRDS OF NORFOLK. 



but several persons believe, and with some show of 

 reason, that a bird, or even two birds, lingered on in this 

 tract till 1843 or even 1845. This last date, however, is 

 the very latest that can be assigned, and the probability, 

 from the evidence available, is in favour of the exter- 

 mination having been thoroughly effected seven years 

 earlier — namely, in 1838. 



Though it is desirable to mark, as has been done, 

 the former existence of two distinct droves of bustards, 

 it must not be inferred that the birds belonging to the 

 one just spoken of in the country round Swaffham, 

 and included entirely in Norfolk, did not occasionally 

 commingle, by the route already indicated, with the 

 other drove haunting the tract nearer Thetford, and 

 stretching from Brettenham and Snarehill, in Norfolk, 

 across the county border to Barnham, North Stow, 

 Icklingham, and much further into Suffolk, till with 

 perhaps a slight interval it joined the tract around 

 Newmarket, celebrated by Ray as a locality for this 

 species, while westward it was only bounded by the fens, 

 .and at Lakenheath became almost conterminous with 

 the southern limits of the Swaffham tract. There is an 

 additional reason, also, for considering this tract sepa- 

 rately from that first spoken of. It seems probable that 

 the causes which effected the extinction of the bustard 

 there had but little to do with it here. Owing to the 

 comparatively poor soil the staple crop of grain in this 

 locality has only very recently been changed from rye to 

 wheat, if, indeed, the change is now entirely consum- 

 mated. Another cause must, therefore, be sought, and 

 this appears to have mainly been the planting of long 

 belts of trees with the object (as briefly stated in the 

 "Introduction") of sheltering the arable land from the 

 violence of the wind, the ill effects of which in blowing 

 the light sand, here chiefly composing the surface soil, 

 is one of the most serious obstacles with which the 



