24 SCIENTIFIC SURVEY OF ABERDEEN AND DISTRICT 
In another way agriculture has diminished and modified the fauna, 
for one of its most characteristic operations is the draining of the land ; 
and the reduction of swamps and marshes, and, with the finer applica- 
tions of draining and cultivation, even of the pools which once gathered 
and remained for weeks at a time upon arable land, has banished the 
habitats of many aquatic creatures. A striking illustration is afforded 
by the disappearance of the disease of ague in Aberdeenshire. Throughout 
the county ague was very prevalent during the eighteenth century, and 
after reaching a climax in the ’eighties, the number of serious cases fell 
off until by the middle of the nineteenth century the disease, as 
endemic, had all but disappeared. ‘The majority of the ague cases were 
malarious, and the carriers of the infecting organism were mosquitoes 
which bred in ponds and pools. It is more than a coincidence that the 
decline of ague in Aberdeenshire corresponded with the period of 
agricultural activity which began towards the end of the eighteenth 
century, and was associated with drainage and the treatment of the 
land with lime, and so with the destruction of the breeding places of 
mosquitoes. 
While agriculture was moulding the fauna in a negative sense by 
cutting off old-established denizens, it was also exercising a profound 
influence in increasing the numbers and range of other members of the 
fauna. The growing of cultivated crops for the sustenance of man and 
his domesticated stock, offered new food supplies to multitudes of wild 
creatures, so that encouragement was given to the multiplication of 
vegetarians amongst mammals, such as rabbits, hares, field-mice and 
voles, to seed-eating birds, such as sparrows and other finches, to the 
multitudes of insects which feed upon the roots, stems, foliage and seed 
of farm crops. Indeed it may be said that the farmer creates his own 
farm pests, and that, so long as his cultivation is successful, he is committed 
(short of extermination) to an endless warfare against a section of the 
native fauna which he has enlarged far beyond its natural or aboriginal 
proportions. 
A secondary result was the increase of the creatures which feed upon 
the farm pests. A single example will illustrate the trend. Previous to 
1850 the starling (Sturnus vulgaris) was only a non-breeding migrant in 
Aberdeenshire, and a rare one at that ; since the ’sixties it has bred in 
increasing numbers, so that now it is abundant everywhere and remains 
all the year round ; even within the boundaries of Aberdeen it has become 
a nuisance because of the roosting colonies of thousands which destroy 
shrubberies by their weight and their excrement. Now examination 
of the food of starlings caught in Aberdeenshire shows that they subsist 
largely upon the ‘ leather-jacket ’ larvae of ‘ daddy-long-legs ’ (Tipulids), 
and beetles abundant in grass land ; so that in particular the laying down 
of pasture has been an incentive to the increase of starlings, and the 
phenomenal increase of starlings throughout Scotland in recent years 
has coincided with the transference of much arable land to pasture. 
Some ADDITIONS TO THE NaTIvE FauNA OF ABERDEENSHIRE.—In 
considering additions to the native fauna I am not thinking of those rare 
individuals which figure largely in local lists, but which are no more 
