NATURAL HISTORY. 
still remains to be cleared up, and many difficult 
anomalies are left unexplained. Most birds are 
migratory to a certain extent, and occasionally shift 
their residences for a greater or less distance.—In 
the district we have limited ourselves to, many 
internal migrations are constantly taking place ;— 
for instance, those of the Golden Plover, Lapwing, 
and Curlew, from Dartmoor to the sea shore, and 
back ;—but it is those only that migrate to con- 
siderable distances, that are usually considered as 
birds of passage. The chief causes of migration 
seem to be ;—a want of adequate and suitable 
food,—a proper temperature,—and a convenient 
situation for breeding and rearing the young. A 
deep and instinctive attachment appears to prevail 
thro’ the whole of animated nature, to the local 
situations, where the earlier portion of existence 
has been spent, and it would perhaps simplify 
the subject, were we to consider that to be the 
natural and proper home of the bird, where it has 
been born and reared ;—which it leaves, not from 
choice, but necessity, and to which it returns, as 
soon as circumstances admit of its doing so;—we 
should thus consider the summer birds as natives, 
that have been compelled to leave their homes for a 
season, and those only that come to us in winter, as 
visitors, in the proper seuse of the word ;—thus 
we have ; 
First :—Permanent residents,—this includes the 
major part of the list. 
