NIGHTINGALE, 
97 
what, then, did the redbreasts feed their foster nestlings, in an 
experiment made by Sir John Sinclair to introduce Nightin¬ 
gales into Scotland ? These Nightingales, we are told, were 
safely reared, flew, and remained in the same vicinity until 
the usual period of their migration ; but the following season 
none returned. 
The line of demarcation being so strongly drawn that 
limits the western range of this species, and which, appa¬ 
rently, they never pass over, we are induced to hazard another 
supposition on the subject, which we leave to future obser¬ 
vation to confirm or confute. As these warblers are invari¬ 
ably found in low, sheltered, and wooded localities, it is 
possible that their nature does not incline them to pass over 
hilly and mountainous boundaries, such as they must sur¬ 
mount in attempting to reach Scotland, or the excluded parts 
of England and Wales; and, consequently, that their dis¬ 
persion over the eastern half of England only, may rather 
be due to its generally level character, than to any of the 
supposed causes before mentioned. 
In support of this conjecture we may observe, that the 
countries on the Continent which are most frequented by 
the Nightingale, are also, in their general aspect, level. 
These are, Holland, Denmark, Sweden, Russia, and Siberia, 
northward; and, to the south, France, parts of Italy and 
Spain, of Germany and Austria. We have frequently re¬ 
marked that Nightingales avoid isolated hills, even of small 
elevation, though covered by wood and pasture, orchards 
and gardens, such as might tempt the sojourn of any sylvan 
warbler; at the same time that, in the low surrounding 
country, they have been plentiful. 
The style of country most resorted to by this species, 
according to our observation, consists of cultivated plains, in¬ 
terspersed with liedgerows and plantations, and hills of gentle 
ascent and very moderate elevation. The presence of rivers 
