THE CAUSES OF THE DECREASE OF BIRDS. 
By Clarence Moores Weed. 
UT of all the recent dis- 
cussion regarding birds 
the fact seems well es- 
tablished that birds as 
a class are now less 
numerous in the United States 
than they were a century or more 
ago. While some species have 
doubtless become more abundant un- 
der the changed conditions of modern 
civilization, others are very much 
rarer, and a few appear to be ap- 
proaching extinction. It, of course, 
was inevitable that the changes pro- 
duced by man’s interference with 
natural conditions should exert a tre- 
mendous influence upon the native 
fauna : some birds have found the 
new dispensation better suited to 
their wants than the old ; others 
have changed their habits and made 
the best of it; while others have 
been so relentlessly persecuted that 
their only hope of survival lay in 
retreating to inaccessible swamps or 
cliffs. The wholesale destruction of 
primeval nesting sites has been a 
potent factor in the changes pro- 
duced, but fortunately many of the 
most useful birds have found substi- 
tutes that answered the purpose very’ 
well : the swallows, for example, 
have gone from hollow trees to the 
eaves and rafters of barns, and the 
swifts from trees to chimneys. The 
great increase of meadow land has 
encouraged the development and dis- 
tribution of birds like the meadow 
lark, originally confined to the prai- 
ries, while the decrease of forests has 
tended to the suppression of species 
like the passenger pigeon that lived 
largely on acorns, beech nuts, or 
other forest products. 
5 
-yvi ■ ’ X v a i 
