52 REV. H. N. BONAR ON THE DECREASE 
And here, for convenience sake, let me name four out of 
the many reasons for the decrease of certain birds :-— 
1. The destruction of birds’ haunts. 
2. Game-preserving. 
3. The greed of man. 
4, The increase of other birds. 
1. The destruction of birds’ haunts. 
The Crane (Grus cinerea), the Bustard (Otis tarda), the 
Bittern (Botaurus stellaris), and the Black Tern (Sterna nigra), 
may be mentioned as representatives of many species which 
now breed no more in our islands, chiefly because men have 
crowded them out of their breeding-grounds. 
Many others are rapidly disappearing for the same reason. 
Take the cases of the Lesser Tern (Sterna minuta) and the 
Roseate Tern (Sterna dougalli), the Ringed Plover (dgialitis 
hiaticula) and the Grey-lag Goose (Anser cinereus), the first 
two of these species being very nearly extinct in our country. 
All these birds lay their eggs on the ground, and have no 
chance of hatching their young when men abound near their 
haunts. Take also the case of a not uncommon bird, the Eider 
Duck (Somateria mollissima), which is rapidly being driven 
away from its nesting-grounds on the east coast of Scotland. 
It still does nest in East Lothian, but in a few years it 
must go. 
The destruction of the forests which used to clothe a large 
part of Scotland has driven away many birds which used 
to breed in trees—ey., the Raven (Corvus corax), which, how- 
ever, still retains a hold as a breeding species by taking to 
cliff-nesting; the Buzzard (Buteo vulgaris), which, alas, I 
now do not dare to call the “Common” Buzzard; the Kite 
(Milvus ictinus) and the Osprey (Pandion haliaetus), owe their 
rarity, in part, to the scarcity of tall trees. 
2. The next cause of decrease is game-preserving. 
I think people fail to realise the very great changes in 
bird-life which the introduction of one single species has 
brought about in our land. 
