concern for the young) was the larger of the two. The difference
in size was compared sometimes at a distance no greater he 10
feet. While studying loon populations it has been remarked
numerous times that usually one parent rushed up to my canoe and
made various demonstrations while the other swam off with the
young. The explanation seemed to be that the behaviour of the
first was indicative of the male parent, and the behaviour of the
second indicative of the female parent. It is not known to me
whether or not there is a constant difference in size between
adult males and females This, no doubt, could be answered by the
measurement of sufficient properly sexed specimens The question
of which sex incubates the eggs could probably only be determined
by collecting incubating birds as they left the nest--a task that
few would care to undertake.

Observations here as elsewhere in British Columbia, suggest
that not all-adult loons breed, that some mated birds do not suc-
ceed in raising young, and that successful pairs are more often
accompanied by one young than by two young. Considering only the
populations observed from June 9, when most, or all the eggs should
have been hatched, it will be seen (Table I) that a total of 42
adults succeeded in raising a total of nine young.

Table I

Loon Populations
No. of No. of

Locality Area of Lake Date adults young

Dragon Lake Bad / 2X decM June 9 4 1
Milburn Lake sige yA iti " 10 af 0)
Summit Lake 7X A/a " 30 5 0
Chief Lake pills July. 7% 2 0)
Nukko Lake 26/4 ex tb es) 4 2
Seymour Lake He 1/2 Mi Neds 6 O
Lacroix Lake Tks dhe lute Ws 1a 2 O
Maclure Lake 3/4 x 3/4 M "15 8 2
Seeley Lake 1/2 x 1/4 M. " 24 2 ©)
Bulkley Lake 2 3/4 x 3/4 M. 1 28 6 0
Shafer Lake 1 x 3/8 M. Aug. 7 i ©)
Bouchie Lake I 27/8 Me " 18 2 ie
Edy Lake 3/4 x 1/2 M. Peers tne 2
Quanstrom Lake 1/4 x 1/4 M. Sept ‘Ghd sul)’ Ghigediels Fee
. Howallsie eae )