n such cases they fly back again until they reach some river or lake
from which the ice has disappeared, where they remain a few days, and
wait the opening of the waters farther north. When they are thus
retarded and sent back, it is always in consequence of some unusual and
unseasonable weather.

The swans go northward to breed. Why they do so is a mystery. Perhaps
they feel more secure in the inhospitable wastes that lie within the
Arctic circle. The Trumpeters breed as far south as latitude 61
degrees, but most of them retire within the frigid zone.

The small swans do not nest so far south, but pursue their course still
onward to the Polar Sea. Here they build immense nests by raising heaps
of peat moss, six feet in length by four in width, and two feet high.
In the top of these heaps is situated the nest, which consists of a
cavity a foot deep, and a foot and a half in diameter.

The Trumpeters and American swans build in marshes and the islands of
lakes. Where the muskrat (_Fiber zibethicus_) abounds, his dome-shaped
dwelling--at that season, of course, deserted--serves often as the
breeding-place boll? for the swans and wild geese. On the top of this
structure, isolated in the midst of great marshes, these birds are
secure from all their enemies--the eagle excepted.

The eggs of the Trumpeter are very large, one of them being enough to
make a good meal for a man. The eggs of the American species are
smaller and of a greenish appearance, while those of the Bewick swan are
still smaller and of a brownish-white colour, with a slight clouding of
darker hue.

Six or seven eggs is the usual "setting." The cygnets, when half or
full-grown, are esteemed good eating, and are much sought after by the
hunters and Indians of the fur countries.

When the cygnets are full-grown, and the frost makes its appearance upon
the lakes and rivers of the hyperborean regions, the swans begin to
shift southwards. They do not migrate directly, as in the spring, but
take more time on their journey, and remain longer in the countries
through which they pass. This no doubt arises from the fact that a
different motive or instinct now urges them. In the spring they are
under the impulse of philo-progenitiveness. Now they range from lake to
lake and stream to stream in search only of food. Again, as in the
spring, the Trumpeters lead the van--winging their way to the great
lakes, and afterwards along the Atlantic coast, and