The following interesting account of the migrations of these birds is given by Franklin: "About the first of September the Swans leave the Polar Sea, and resort to the lakes and rivers in and about the latitude of Hudson's Bay; there they remain till October, preparing for their departure for the winter, when they collect in flocks of from twenty to thirty, and seizing a favourable opportunity, with the wind not opposed to the direction of their flight, they mount high in the air, form a prolonged wedge, and with loud screams depart for more genial climes. While making either their semi-annual transmigration, or on shorter expeditions, an occasional scream, equal to, 'How do you all come on behind?' issues from the leader, which is always replied to by some posterior Swan with an 'All's well!' vociferation. When the leader of the party becomes fatigued with his extra duty of cutting the air, he falls into the rear, and his neighbour takes his place. When mounted, as they sometimes are, several thousand feet above the earth, with their delicate outline scarcely perceptible against the clear blue of heaven, this harsh sound, softened and modulated by distance, and issuing from the immense void above, assumes a supernatural kind of tone." The permanent habitat of the Swans is always upon large lakes of fresh water, or in marshy situations where fresh water is abundant. During their migrations, however, they take up a temporary residence on water of any kind. Their nests are generally placed on rivers or fresh-water lakes, but probably this is only on account of the shallowness of such situations, as after the breeding season some betake themselves to the sea, or wherever food is most abundantly procurable. The Swans are only active in the day, and even their migrations are never carried on by night. In their locomotive capabilities they surpass most other Swimming Birds. Their domain is the water, and it is only unwillingly that they ever venture on dry land; nor do they readily take wing, unless compelled to do so by unavoidable necessity. The very backward position of their legs renders walking on land difficult, so that when on dry ground their gait is heavy and vacillating. Their flight apparently requires considerable effort, more especially when they attempt to rise from the surface of the water; when, however, they have gained a certain altitude, it is extremely rapid. It would appear almost impossible for these birds to rise from the ground, and they never venture to alight on dry land. When beginning their flight from the water, they always stretch out their necks horizontally to their full length, striking the surface with their wings, and splashing with their broad-soled feet; and thus, half flying and half walking, they proceed for a distance of from forty to eighty feet, before they can acquire impetus to enable them to mount into the air. When, however, this is once accomplished, their movements are perfectly easy and free.