2008 Summary

We were able to get on the water and band scoters on 24 of the 28 days scheduled.  Three of the four days without effort were due to poor weather conditions; the forth day was due to a lack of molting scoters at the end of the season.  We had good success capturing in the southern areas (Padilla Bay and Forbes Point) and mixed success on Boundary Bay and the Fraser River Delta. This mixed success was largely due to the poor weather conditions encountered during the capture periods when we were schedule to capture there.

We averaged 26.6 scoters per net set over the entire season, with a total of 49 net sets deployed (1302 scoters captured).  Net set averages varied by site, with Padilla Bay having the greatest success per set, averaging 46.6 scoters banded per set.  The other areas averaged much lower, ranging from 13.2 to 18.4 scoters banded per set.

Species and sex composition also varied by site.  Padilla Bay was the more unique site being comprised of entirely of Surf Scoters, with the majority of these being female (82%).  ATY (after third year) females comprised 83% of all females captured there.  Species composition at Forbes Point was nearly split (46% WWSC, 54% SUSC).  Of the SUSC there, females and males comprised roughly 50% each, while males comprised 85% of the WWSC.  Like Forbes Point, Boundary Bay was nearly equally split between the two species (46% WWSC, 54% SUSC).  SUSC sex composition was female biased (67% female, 33% male), and WWSC were male biased (11% female, 89% male).  The Fraser River Delta was the only site with a WWSC bias (57% WWSC, 43% SUSC).  The sexual compositions of WWSC’s were similar here as the other sites where this species was present (11% female, 89% male).  This location was also male biased for the SUSC (67% male, 33% female).

It is not a surprise that our sample of female WWSC is low.  Just as our past satellite telemetry studies indicated, the majority of adult females molt on the interior lakes of northern Canada, not far from the nesting lakes.

Table 1.  Banding summary from the 2008 season, By Capture Location.

Banding Totals by Location Location Forbes Point Padilla Bay Boundary Bay Fraser River Totals
Sets 15 18 9 7 49
Birds/Set 14.5 46.6 13.2 18.4 26.6
Region PS PS SOG SOG  
WWSC Male HY 0 0 0 0 0
SY 3 0 0 0 3
TY 14 0 4 9 27
SY/TY 8 0 2 2 12
ATY 59 0 43 55 157
AHY 1 0 0 0 0
Total 85 0 49 66 200
Female HY 0 0 0 0 0
SY 0 0 0 1 1
TY 0 0 0 1 1
SY/TY 6 0 1 0 7
ATY 9 0 5 6 20
AHY 0 0 0 0 0
Total 15 0 6 8 29
M+F Total 100 0 55 74 229
SUSC Male HY 0 0 0 0 0
SY 2 2 0 0 4
TY 7 30 5 5 47
SY/TY 8 68 9 2 87
ATY 43 53 7 31 134
AHY 0 1 0 0 1
Total 60 154 21 38 273
Female HY 0 0 0 0 0
SY 0 21 2 1 24
TY 3 41 0 1 45
SY/TY 8 50 4 0 62
ATY 46 572 37 15 670
AHY 0 0 0 0 0
Total 57 684 43 17 801
M+F Total 117 838 64 55 1074
All Scoters Male HY 0 0 0 0 0
SY 5 2 0 0 7
TY 21 30 9 14 74
SY/TY 16 68 11 4 99
ATY 102 53 50 86 291
AHY 1 1 0 0 2
Total 145 154 70 104 473
Female HY 0 0 0 0 0
SY 0 21 2 2 25
TY 3 41 0 2 46
SY/TY 14 50 5 0 69
ATY 55 572 42 21 690
AHY 0 0 0 0 0
Total 72 684 49 25 830
M+F Total 217 838 119 129 1302

Molt chronology

The timing of molt for the WWSC did not vary much between sexes.  The sample size, and timing of samples was not ideal, so a better sample during the 2009 season should provide a better picture of molt chronology for this species. 

There was variation between sexes for the SUSC.  Males had a more drawn out peak than the females, and on average molted earlier than the females.  We have a nice picture from the females, from beginning to end, but we began too late to capture the beginning of the males.  We will begin efforts earlier in 2009 to better capture this.  We did not look at variation between sites.