SYLVIADEH, OR WARBLERS. 39 
globe, are destined to perform an important part in the 
economy of nature: to them appears intrusted the 
subjugation of those innumerable minute insects which 
lurk within the buds, the foliage, or the flowers of 
plants ; and thus protected, escape that destruction from 
swallows, to which they are only exposed during flight. 
The diminutive size of such insects renders them unfit 
for the nourishment of the thrushes and the larger in- 
sectivorous birds, while their number and variety only 
become apparent when the boughs are shaken, and their 
retreat disturbed. How enormous, then, would be their 
multiplication, had not nature provided other races of 
beings to check their increase! No birds appear more 
perfectly adapted for this purpose than are the warblers. 
They appear among us, for the most part, on the first 
appearance of spring, when the insect world is called into 
life and activity, by the renewal of vegetation; and they 
depart towards autumn, when these minute depredators 
diminish, and when the services of their enemies are 
consequently no longer required. As different localities 
are assigned to different tribes of insects, so do we find 
a similar diversity of haunts among the various groups 
of warblers. The gold crests and wood warblers 
(Sylviane) confine themselves principally to the higher 
“trees, where they search for winge’ insects among the 
foliage; or capture them, like flycatchers, when at- 
tempting to escape. The reed warblers and the 
nightingales ( Philomeline) haunt the vicinity of waters, 
or the more dense foliage of hedges, for insects peculiar 
to such situations. The stonechats (Sawicoline), on 
the contrary, prefer dry commons and wide extended 
plains, and feed on insects appropriated to these local- 
ities: while those which belong to humid and wet 
places are the particular food of the wagtails and tit- 
 larks (Motucilline): lastly, the Puriane, or titmice, 
search with the greatest assiduity among the buds and 
tender shoots of trees, and thus destroy a host of hidden 
enemies, inimical to vegetation. The natural distribution 
_ Of this family i is thus marked by Becuionties of bat 
D 4 
