1926]  Swarth: Birds and Mammals from the Atlin Region 55

in many places by tracts of swamp, grass-covered or grown up with
willow thickets, and the woods are interspersed with many small lakes.
Three or four miles east of Atlin, Lake Como, the largest of these
small lakes near the town, supports a considerable population of
water birds.

Some four miles south of Atlin, Monarch Mountain rises (see pl. 6,
fig. 5), the nearest peak of a series of rounded and, for the most part,
not particularly rugged mountains, that border Pine Creek Valley to
the eastward of Atlin and the lake shore to the southward. Conditions
on this mountain may be briefly described, as generally applicable to
that type of country in this region. Poplar woods border the lowest
slopes of the mountain, but ascend its sides only a few hundred feet
before giving way to the belt of darker and denser spruce. Between
3500 and 4000 feet altitude spruce is largely replaced by balsam fir,
growing to large size at its lowest level and persisting over the summit
of the peak in more or less dwarfed and prostrate form. At the upper
edge of the spruce belt the woods become more thin, and are cleft by
wider and wider areas of open grass or lupine covered slopes. On
the summit (3800 to 5000 feet altitude) upright timber of any size
disappears, save in a few sheltered spots, and the scattered thickets of
serubby balsam sprawling close to earth are surrounded by wide areas
of open ground, grass covered or here and there grown up with false
heather over limited damp areas. Creeping birch grows here, too, and
in extensive tracts; on this particular mountain I saw little that was
more than knee-high.

Directly opposite the town of Atlin lies a group of three islands,
the nearest within a quarter of a mile from the shore, and none of
them more than a few acres in extent (see pl. 5, fig. 2). A striking
feature of these islands is the fact that of the forest trees with which
they are covered nearly all are balsam fir. There are relatively few
spruce or jack pine. On the adjacent mainland I saw no balsam at the
lake level. The islands are the nesting grounds of small colonies of
water birds (short-billed gull, Bonaparte gull, and Arctic tern) and
they harbor an extraordinary number of small land birds. We listed
fifteen species of land birds as nesting there, some of them (such as the
black-poll warbler) extremely scarce on the neighboring mainland.
These small birds, too, were rearing their young successfully, in con-
trast to conditions on the mainland, where subsequent destruction of
nest, eggs, or young was the usual fate of most of the nests we found.
On the islands there were no red squirrels, no chipmunks, and no