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seven shoveller, four of the last probably being transients, were
observed at different times in the region adjacent to Quesnel and
west of that place None of these species was recorded in more
northern latitudes. Redhead and ruddy duck were absent and only
five canvas back. 4 males and 1 female, were observed during the
entire season. Coots were conspicuously absent on most marshes
and represented by only a few pairs on others.

The absence of redhead, canvas-back, ruddy duck, the absence
of blue-winged teal and cinnamon teal except in the most southern
parts, and the rarity of the coot might be explained by the fact
that the region generally is beyond the range-periphery of the
Species as developed west of the Rocky Mountains. What limits
their expansion in space cannot be explained by the presence or
absence of any known physical factors. Perhaps it may be attri-
buted to physical elements or limitations inherent in the species
themselves. In contrast it can be observed how the mallard has
expanded over the continent from California to Alaska.

The absence of pintail and shoveller (species that nest in
Alaska and the Yukon) as nesting elements in the population is
even less readily accounted for. It might be suggested that duck
populations within more or less definite geographical boundaries
are static in that they do not expand beyond those boundaries.

-The size of the population rises and falls in response to condi-
tions of water and food, and in response to other factors that may
be favourable in some years and unfavourable in others. Natives
of any given area and their increase return to the same area each
year (the recovery of banded mallards and pintails shows that
units of population travel together in successive years), and if
conditions are unfavourable some may not breed, or nest unsuccess-—
fully, but nevertheless few or none seek more favourable condi-
tions outside the boundaries of the region to which they are native.

Certain lakes and marshes of central British Columbia which
are relatively barren of waterfowl in summer attract large numbers
of ducks and geese during migrations. Many observers have reported
this in respect of particular waters such as Bulkley Lake, Francois
Lake and the Nechako River.

Nesting grounds north of the region explored, in which river
margins figure prominently, are reported by travellers as populated
chiefly by Canada goose, mallard, and American merganser.

Finally in summary it may be said that one of the most interest—
ing facts brought out by this investigation is that many waters in
central British Columbia suited to waterfowl propagation have in-
significant populations or are entirely devoid of waterfowl.

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