THE DECREASE AND INCREASE OF CERTAIN BIRDS. 51 
THE DECREASE AND INCREASE OF CERTAIN 
BIRDS IN SCOTLAND. 
By the Rev. H. N. Bonar, M.B.O.U. 
(Read Ist December 1898.) 
THE relation of all birds to each other when subject to no 
human interference must have been a most delicately ad- 
justed affair. I do not mean to affirm that it was finally 
fixed, but I can safely say that, compared with the conditions 
which exist at present, it was at least stable. 
When human beings multiplied sufficiently for their 
numbers to make any perceptible difference on the face of 
the land, then began the disturbance of the conditions under 
which all wild creatures had previously existed. Forests 
and thickets were cleared away, swamps and lakes were 
drained, filth was poured into rivers, and poisonous smoke 
into the air. Towns sprang up where wildernesses had 
been, and birds and beasts were either exterminated or 
driven to seek more inaccessible spots. 
All this was inevitable ; the advance of civilisation necessi- 
tated it, and a man is better than a bird or beast. 
And here the increase of certain birds comes in. Birds, 
plain enough in their plumage, nasty enough in their flesh, 
tuneless enough in their note to escape persecution, began 
to reap benefit from the presence of man. They found that, 
wherever men were, there was always a minimum of food 
(even in the hardest winter), along with a certain amount 
of shelter and, perhaps, unconscious protection from their 
natural enemies. They then began to alter their habits, and 
eradually to conform to their new surroundings. 
But, so far, those disturbances of the balance of nature 
were nearly always necessary, though regrettable. It was 
at this stage that men set to work to make bad worse. 
