Preliminary report trends in duck breeding populations, 1955-2006

              PRELIMINARY REPORT
TRENDS IN DUCK BREEDING POPULATIONS, 1955-2006
Khristi A. Wilkins and Mark C. Otto
U.S. Fish and Wildlife Service
Division of Migratory Bird Management
11510 American Holly Drive
Laurel, MD 20708-4002
Administrative Report – June 30, 2006
This preliminary report summarizes information about the status of duck populations and
wetland habitats during spring 2006, focusing on areas encompassed by the U.S. Fish and
Wildlife (USFWS) and Canadian Wildlife Services’ (CWS) Waterfowl Breeding
Population and Habitat Survey. This preliminary report does not include estimates from
the eastern survey area or information from surveys conducted by State or Provincial
agencies. A final report including survey results from the eastern survey area will
be issued. In the traditional survey area, which includes strata 1-18, 20-50, and 75-77
(Fig. 1), the total duck population estimate (excluding scoters [Melanitta spp.], eiders
[Somateria and Polysticta spp.], long-tailed ducks [Clangula hyemalis], mergansers
[Mergus and Lophodytes spp.], and wood ducks [Aix sponsa]) was 36.2 ± 0.6 [SE]
million birds. This was 14% greater than last year’s estimate of 31.7 ± 0.6 million birds
and 9% above the 1955-2005 long-term averagea. Mallard (Anas platyrhynchos)
abundance was 7.3 ± 0.2 million birds, which was similar to last year’s estimate of 6.8 ±
0.3 million birds and the long-term average. Blue-winged teal (A. discors) abundance
was 5.9 ± 0.3 million birds. This value was 28% greater than last year’s estimate of 4.6 ±
0.2 million birds and 30% above the long-term average. The estimated abundance of
green-winged teal (A. crecca; 2.6 ± 0.2 million) was 20% greater than last year and 39%
above the long-term average. The estimated number of gadwall (A. strepera; 2.8 ± 0.2
million) was 30% greater than last year and was 67% above the long-term average,
whereas the estimated number of redheads (Aythya americana; 0.9 ± 0.1 million)
increased 55% over 2005 and was 47% above the long-term average. The abundance of
canvasbacks (A. valisineria; 0.7 ± 0.1 million) increased 33% over last year and was 23%
over the long-term average. Northern shovelers (Anas clypeata; 3.7 ���� 0.2 million) were
69% above their long-term average. Although the abundances of most species increased
over last year and were greater than their long-term averages, American wigeon (A.
a Populations are considered to have changed from the previous year or long-term average if observed
significance value associated with change is ≤ 0.10. Actual p-values are given in tables.
1
americana; 2.2 ± 0.1 million) and scaup (Aythya affinis and A. marila combined; 3.2 ±
0.2 million) were 17% and 37% below their long-term averages, respectively. The
estimate for scaup was a record low for the second consecutive year. The abundance of
northern pintails (Anas acuta; 3.4 ± 0.2 million) was 18% below the 1955-2005 average,
although this year’s estimate was 32% greater than that of last year.
Despite a very warm winter, the quality of habitat for breeding waterfowl in the U.S. and
Canada is slightly better this year than last year. Improvements in Canadian and U.S.
prairie habitats were primarily due to average to above-average precipitation, warm
spring temperatures, and carry-over effects from the good summer conditions of 2005.
Improved habitat conditions were reflected in the higher number of ponds counted in
Prairie Canada this year compared to last year. The 2006 estimate of ponds in Prairie
Canada was 4.4 ± 0.2 million ponds, a 13% increase from last year’s estimate of 3.9 ± 0.2
million ponds and 32% above the 1955-2005 average. The parkland and northern
grassland regions of Manitoba and Saskatchewan received abundant rain in March and
April, which created good to excellent habitat conditions. Higher water tables prevented
farm activities in wetland basins and excellent residual nesting cover remained around the
potholes. Many of the wetlands flooded beyond their normal basins and into the
surrounding uplands. Deeper water in permanent and semi-permanent wetlands, coupled
with increased amounts of flooded emergent vegetation and woodland, likely benefited
diving ducks and overwater- and cavity-nesting species. However, spring precipitation in
the grasslands of southern Saskatchewan and extreme southwestern Manitoba was
insufficient to fill seasonal and semi-permanent wetlands or create temporary wetlands
for waterfowl, leaving these regions in fair or poor condition at the time of the survey.
Above-average precipitation in the fall and spring in parts of southern Alberta improved
conditions in this historically important pintail breeding region. This region has been dry
since 1998, with the exception of 2003. However, central Alberta remained dry.
Habitat conditions in the U.S prairies were more variable than those in the Canadian
prairies. The 2006 pond estimate for the north-central U.S. (1.6 ± 0.1 million) was
similar to last year’s estimate and the long-term average. The total pond estimate (Prairie
Canada and U.S. combined) was 6.1 ± 0.2 million ponds. This was 13% greater than last
year’s estimate of 5.4 ± 0.2 million and 26% higher than the long-term average of 4.8 ±
0.1 million ponds. Habitat quality improved minimally in the easternmost regions of
North and South Dakota relative to 2005. Small areas of the Eastern Dakotas were in
good-to-excellent condition, helped by warm April temperatures and spring rains that
advanced vegetation growth by about 2 weeks. However, most of the Drift Prairie, the
Missouri Coteau, and the Coteau Slope remained in fair to poor condition due to lack of
temporary and seasonal water and the deteriorated condition of semi-permanent basins.
Permanent wetlands and dugouts were typically in various stages of recession. The
Western Dakotas were generally in fair condition. Most wetland and upland habitats in
Montana benefited modestly from average to above-average fall and winter precipitation
and improvements in nesting habitat last year. Spring precipitation in Montana during
March and April also helped to mitigate several years of drought. A large portion of
central Montana was in good condition due to ample late winter and early spring
precipitation. Biologists also noted improvements in upland vegetation over previous
2
years. In this central region, most pond basins were full and stream systems were
flowing. However, nesting habitat was generally fair to poor for most of the northern
portion of Montana.
Habitat conditions in most northern regions of Canada were improved over last year due
to an early ice break-up, warm spring temperatures, and good precipitation levels. In
northern Saskatchewan, northern Manitoba, and western Ontario, winter snowfall was
sufficient to recharge most beaver ponds and small lakes. Larger lakes and rivers tended
to have higher water levels than in recent years. Conditions in the smaller wetlands were
ideal. However, in northern Manitoba and northern Saskatchewan, some lakes associated
with major rivers were flooded, with some flooded well into the surrounding upland
vegetation. The potential for habitat loss due to flooding caused biologists to classify this
region as good. In Alberta, water levels improved to the north, except for the Athabasca
Delta, where wetlands, especially seasonal wetlands, generally had low water levels.
Most of the Northwest Territories had good water levels. Exceptions were the southern
part of the Territory where heavy rains in May caused some flooding of nesting habitat,
and a dry swath across the central part of the province. In contrast to most of the survey
region and to the past few years, spring did not arrive early in Alaska this year. Overall,
a more normal spring phenology occurred throughout most of Alaska and the Yukon
Territory, with ice lingering in the following regions: the outer coast of the Yukon Delta,
the northern Seward Peninsula, and on the Old Crow Flats. Some flooding occurred on a
few major rivers. Overall, good waterfowl production is anticipated this year from the
northwestern continental area if temperatures remain seasonable.
Spring-like conditions also arrived early in the East, with an early ice break-up and
relatively mild temperatures. Biologists reported that habitat conditions were generally
good across most of the survey area. Most regions had a warm, dry winter and a dry start
to spring. Extreme southern Ontario was relatively dry during the survey period and
habitats were in fair to poor condition. However, precipitation after survey completion
improved habitat conditions in this region. Abundant rain in May improved water levels
in Maine, the Maritimes, southern Ontario, and Quebec, but caused some flooding in
southern Ontario and Quebec and along the coast of Maine, New Brunswick, and Nova
Scotia. In Quebec, a very early spring assured good habitat availability. Despite the
early spring and the abundance of spring precipitation, a dry winter still left most of the
marshes and rivers drier than in past years. Many bogs were noticeably drier than past
years or dry entirely in a few cases. Winter precipitation increased to the west and north,
resulting in generally good levels in central and northern Ontario. Conditions were good
to excellent in central and northern Ontario due to the early spring phenology, generally
good water levels, and warm spring temperatures.
3
The data in this report were contributed by the following individuals:
Alaska, Yukon Territory, and Old Crow Flats (Strata 1-12): B. Conant and E. Mallek
Northern Alberta, Northeastern British Columbia, and Northwest Territories (Strata 13-18, 20,
and 77): C. Ferguson and D. Benning d
Northern Saskatchewan and Northern Manitoba (Strata 21-24): F. Roetker and B. Fortier
Southern and Central Alberta (Strata 26-29, 75, and 76):
Air E. Huggins and C. Pyle
Ground P. Pryor a, K. Froggatt b, S. Barry a, E. Hofman b, M. Barr c, D. Chambers c,
N. Clements a, N. Fontaine c, J. Going a, R. Hunka c, T. Mathews c, I. McFarlane c,
B. Peers c, C. Pinto b, and R. Talbot c
Southern Saskatchewan (Strata 30-35):
Air P. Thorpe, T. Lewis, R. King, and S. Frazer
Ground D. Nieman a, J. Smith a, K. Warner a, D. Caswell a, J. Caswell a, J. Leafloor a,
P. Rakowski a, M. Schuster a, B, Bartzen a, K. Dufour a, C. Downie a, P. Nieman a,
L. Sitter a, R. Spencer a, A. Williams c, F. Baldwin a, L. Beaudoin a, S. Lawson c,
C. Meuckon a, N. Wiebe a, and K. Wilkins
Southern Manitoba (Strata 25 and 36-40):
Air R. King and S. Frazer
Ground D. Caswell a, G. Ball b, J. Caswell a, J. Leafloor a, P. Rakowski a, M. Schuster a,
F. Baldwin a, L. Beaudoin a, S. Lawson c, C. Meuckon a, N. Wiebe a, and
K. Wilkins
Montana and Western Dakotas (Strata 41-44):
Air R. Bentley and K. Richkus
Ground P. Garrettson and M. Carpenter
Eastern Dakotas (Strata 45-49):
Air J. Solberg and M. Rich
Ground K. Kruse, M. Grovijahn b, B. McDermott, and D. Whittington
Central Quebec (Strata 68-70):
Air J. Wortham, D. Fronczak, and G. Boomer
Helicopter D. Holtby b and G. Boomer
New York, Eastern Ontario, Hudson and James Bay Lowlands of Ontario, and Southern Quebec
(Strata 52-59):
Air M. Koneff, M. Jones, and R. Raftovich
4
Central and Western Ontario (Strata 50 and 51):
Air K. Bollinger and J. Bredy
Maine and Maritimes (Strata 62-67):
Air J. Bidwell, H. Obrecht, and J. Goldsberry d
Habitat information was provided by U.S. Fish and Wildlife Service and Canadian Wildlife
Service biologists.
a Canadian Wildlife Service
b State, Provincial, or Tribal Conservation Agency
c Ducks Unlimited - Canada
d Other organization
All others – U.S. Fish and Wildlife Service
5
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6
Table 1. Duck breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA a % P
Alaska-Yukon Territory
– Old Crow Flats 4,755 5,114 -7 0.149 3,550 +34 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 5,132 4,713 +9 0.222 7,153 -28 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 2,711 3,223 -16 0.047 3,557 -24 <0.001
S. Alberta 4,581 3,178 +44 <0.001 4,283 +7 0.121
S. Saskatchewan 10,096 7,967 +27 <0.001 7,348 +37 <0.001
S. Manitoba 1,796 1,627 +10 0.137 1,544 +16 0.003
Montana and western Dakotas 1,910 1,290 +48 <0.001 1,613 +18 0.001
Eastern Dakotas 5,181 4,623 +12 0.073 4,201 +23 <0.001
Total b 36,160 31,735 +14 <0.001 33,251 +9 <0.001
a Long-term average, 1955-2005.
b Includes 10 species in Appendix A plus American black duck, ring-necked duck, goldeneyes, bufflehead, and ruddy duck; excludes eiders, long-tailed duck, scoters,
mergansers, and wood duck.
Table 2. Mallard breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 516 703 -27 0.009 357 +44 0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 558 533 +5 0.818 1,086 -49 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 656 937 -30 0.116 1,159 -43 <0.001
S. Alberta 901 671 +34 0.006 1,099 -18 <0.001
S. Saskatchewan 1,832 1,729 +6 0.530 2,072 -12 0.021
S. Manitoba 511 455 +12 0.351 378 +35 0.004
Montana and western Dakotas 679 387 +76 <0.001 499 +36 0.002
Eastern Dakotas 1,624 1,340 +21 0.140 846 +92 <0.001
Total 7,277 6,755 +8 0.147 7,496 -3 0.338
7
Table 3. Gadwall breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 2 3 -29 0.739 2 0 0.998
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 135 77 +75 0.102 47 +187 0.006
N. Saskatchewan- N. Manitoba
- W. Ontario 16 19 -14 0.747 27 -41 0.042
S. Alberta 455 338 +35 0.152 309 +47 0.010
S. Saskatchewan 1,202 723 +66 0.006 556 +116 <0.001
S. Manitoba 125 120 +4 0.820 67 +88 <0.001
Montana and western Dakotas 216 187 +16 0.474 194 +11 0.476
Eastern Dakotas 673 712 -6 0.642 491 +37 <0.001
Total 2,825 2,179 +30 0.003 1,692 +67 <0.001
Table 4. American wigeon breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 822 873 -6 0.552 511 +61 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 570 583 -2 0.921 912 -38 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 105 174 -40 0.080 253 -58 <0.001
S. Alberta 189 125 +50 0.025 296 -36 <0.001
S. Saskatchewan 282 294 -4 0.845 425 -34 <0.001
S. Manitoba 16 34 -53 0.086 62 -74 <0.001
Montana and western Dakotas 120 67 +79 0.008 109 +10 0.531
Eastern Dakotas 67 73 -8 0.767 48 +39 0.140
Total 2,171 2,225 -2 0.766 2,617 -17 <0.001
8
Table 5. Green-winged teal breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 780 713 +9 0.471 358 +118 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 751 437 +72 0.018 752 0 0.990
N. Saskatchewan- N. Manitoba
- W. Ontario 303 310 -2 0.896 197 +54 0.001
S. Alberta 178 159 +12 0.720 194 -8 0.709
S. Saskatchewan 401 359 +12 0.632 230 +75 0.007
S. Manitoba 65 55 +19 0.448 52 +27 0.215
Montana and western Dakotas 34 83 -59 0.005 40 -15 0.364
Eastern Dakotas 75 42 +81 0.164 45 +67 0.164
Total 2,587 2,157 +20 0.031 1,867 +39 <0.001
Table 6. Blue-winged teal breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 0 3 -100 0.339 1 -100 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 316 247 +28 0.456 270 +17 0.515
N. Saskatchewan- N. Manitoba
- W. Ontario 82 139 -41 0.237 265 -69 <0.001
S. Alberta 864 649 +33 0.126 609 +42 0.015
S. Saskatchewan 2,228 1,597 +40 0.019 1,218 +83 <0.001
S. Manitoba 426 339 +26 0.117 382 +11 0.329
Montana and western Dakotas 346 286 +21 0.240 263 +32 0.047
Eastern Dakotas 1,598 1,325 +21 0.171 1,492 +7 0.418
Total 5,860 4,586 +28 0.001 4,501 +30 <0.001
9
Table 7. Northern shoveler breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 409 666 -39 0.003 267 +53 0.002
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 193 213 -10 0.690 213 -10 0.498
N. Saskatchewan- N. Manitoba
- W. Ontario 12 29 -59 0.016 43 -72 <0.001
S. Alberta 701 548 +28 0.190 360 +95 <0.001
S. Saskatchewan 1,612 1,314 +23 0.210 648 +149 <0.001
S. Manitoba 178 211 -16 0.430 107 +66 <0.001
Montana and western Dakotas 163 148 +10 0.612 149 +9 0.514
Eastern Dakotas 414 464 -11 0.477 389 +6 0.594
Total 3,680 3,591 +2 0.765 2,177 +69 <0.001
Table 8. Northern pintail breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 1,041 905 +15 0.310 913 +14 0.174
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 126 108 +16 0.662 378 -67 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 6 8 -31 0.470 41 -86 <0.001
S. Alberta 611 282 +116 <0.001 721 -15 0.107
S. Saskatchewan 1,024 858 +19 0.343 1,218 -16 0.203
S. Manitoba 57 68 -16 0.480 112 -49 <0.001
Montana and western Dakotas 264 75 +252 <0.001 269 -2 0.907
Eastern Dakotas 257 256 +1 0.968 459 -44 <0.001
Total 3,386 2,561 +32 0.001 4,111 -18 <0.001
10
Table 9. Redhead breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 10 <1 +4000 0.106 1 +622 0.154
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 59 49 +19 0.679 38 +54 0.143
N. Saskatchewan- N. Manitoba
- W. Ontario 5 13 -61 0.050 28 -82 <0.001
S. Alberta 154 91 +69 0.074 116 +33 0.214
S. Saskatchewan 435 226 +93 0.007 190 +129 0.001
S. Manitoba 102 98 +4 0.903 72 +42 0.127
Montana and western Dakotas 12 3 +315 0.054 9 +25 0.573
Eastern Dakotas 139 112 +25 0.389 169 -17 0.284
Total 916 592 +55 0.001 624 +47 0.001
Table 10. Canvasback breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 73 95 -23 0.542 91 -20 0.475
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 109 98 +12 0.771 73 +50 0.177
N. Saskatchewan- N. Manitoba
- W. Ontario 13 39 -67 0.068 55 -77 <0.001
S. Alberta 76 43 +79 0.105 64 +20 0.440
S. Saskatchewan 287 162 +76 0.026 182 +57 0.037
S. Manitoba 87 48 +84 0.166 56 +56 0.221
Montana and western Dakotas 12 5 +157 0.121 8 +58 0.321
Eastern Dakotas 33 31 +5 0.875 33 0 1.000
Total 691 521 +33 0.051 562 +23 0.067
11
Table 11. Scaup (greater and lesser combined) breeding population estimates (in thousands) for regions in the traditional
survey area.
Change from 2005 Change from LTA
Region 2006 2005 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 884 961 -8 0.500 915 -3 0.680
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 1,169 1,361 -14 0.316 2,627 -55 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 335 349 -4 0.816 587 -43 <0.001
S. Alberta 214 127 +69 0.071 353 -39 0.001
S. Saskatchewan 391 381 +3 0.918 416 -6 0.714
S. Manitoba 97 60 +61 0.146 135 -28 0.103
Montana and western Dakotas 19 16 +14 0.723 53 -65 <0.001
Eastern Dakotas 138 132 +5 0.854 97 +42 0.097
Total 3,247 3,387 -4 0.586 5,184 -37 <0.001
12
Table 12. Estimated number (in thousands) of May ponds in portions of prairie and parkland Canada and the northcentral U.S.
Change from 2005 Change from LTA
Survey Area 2006 2005 % P LTA a % P
Prairie Canada
S. Alberta 996 750 +33 0.020 722 +38 <0.001
S. Saskatchewan 2,719 2,415 +13 0.250 1,963 +38 <0.001
S. Manitoba 735 755 -3 0.805 673 +9 0.351
Subtotal 4,450 3,921 +13 0.074 3,358 +32 <0.001
Northcentral U.S.
Montana and western Dakotas 615 663 -7 0.512 528 +16 0.064
Eastern Dakotas 1,030 798 +29 0.011 994 +4 0.625
Subtotal 1,644 1,461 +13 0.116 1,522 +8 0.159
Grand Total 6,094 5,381 +13 0.025 4,830 +26 <0.001
aLong-term average. Prairie and parkland Canada, 1961-2005; northcentral U.S. and Grand Total, 1974-2005.
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Millions
Northcentral U.S.
Prairie Canada
Total
Year
Figure 2. Number of ponds in May and 95% confidence intervals in prairie Canada and the northcentral U.S.
13
Poor
Fair
Good
Excellent
Figure 3. Breeding waterfowl habitat conditions during the 2006 Waterfowl Breeding Population and Habitat Survey, as judged by U.S. Fish
and Wildlife Service Flyway Biologists.
14
Figure 4. Breeding waterfowl habitat conditions during May and June 2005, as judged by U.S. Fish and Wildlife Service Flyway Biologists.
Poor
Fair
Good
Excellent
15
Figure 5. Breeding population estimates, 95% confidence intervals, and North American Waterfowl Management
Plan population goal (dashed line) for selected species in the traditional survey area (strata 1-18, 20-50, 75-77).
Mallard
0
2
4
6
8
10
12
14
1955 1965 1975 1985 1995 2005
Year
Millions
American wigeon
0
1
2
3
4
5
1955 1965 1975 1985 1995 2005
Year
Millions
Gadwall
0
1
2
3
4
5
1955 1965 1975 1985 1995 2005
Year
Millions
Blue-winged teal
0
1
2
3
4
5
6
7
8
9
1955 1965 1975 1985 1995 2005
Year
Millions Green-winged teal
0
1
2
3
4
1955 1965 1975 1985 1995 2005
Year
Millions
Total ducks
20
25
30
35
40
45
50
1955 1965 1975 1985 1995 2005
Year
Millions
16
Figure 5 (continued).
Northern pintail
0
2
4
6
8
10
12
1955 1965 1975 1985 1995 2005
Year
Millions
Canvasback
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1955 1965 1975 1985 1995 2005
Year
Millions
Redhead
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1955 1965 1975 1985 1995 2005
Year
Millions
Scaup
0
2
4
6
8
10
1955 1965 1975 1985 1995 2005
Year
Millions
Northern shoveler
0
1
2
3
4
5
1955 1965 1975 1985 1995 2005
Year
Millions
17
Appendix A. Breeding population estimates and standard errors (in thousands) for 10 species of ducks from the
traditional survey area (strata 1-18, 20-50, 75-77).
Mallard Gadwall American wigeon Green-winged teal Blue-winged teal
Year Nˆ
E Sˆ Nˆ
E Sˆ Nˆ
E Sˆ Nˆ
E Sˆ Nˆ
SˆE
1955 8777.3 457.1 651.5 149.5 3216.8 297.8 1807.2 291.5 5305.2 567.6
1956 10452.7 461.8 772.6 142.4 3145.0 227.8 1525.3 236.2 4997.6 527.6
1957 9296.9 443.5 666.8 148.2 2919.8 291.5 1102.9 161.2 4299.5 467.3
1958 11234.2 555.6 502.0 89.6 2551.7 177.9 1347.4 212.2 5456.6 483.7
1959 9024.3 466.6 590.0 72.7 3787.7 339.2 2653.4 459.3 5099.3 332.7
1960 7371.7 354.1 784.1 68.4 2987.6 407.0 1426.9 311.0 4293.0 294.3
1961 7330.0 510.5 654.8 77.5 3048.3 319.9 1729.3 251.5 3655.3 298.7
1962 5535.9 426.9 905.1 87.0 1958.7 145.4 722.9 117.6 3011.1 209.8
1963 6748.8 326.8 1055.3 89.5 1830.8 169.9 1242.3 226.9 3723.6 323.0
1964 6063.9 385.3 873.4 73.7 2589.6 259.7 1561.3 244.7 4020.6 320.4
1965 5131.7 274.8 1260.3 114.8 2301.1 189.4 1282.0 151.0 3594.5 270.4
1966 6731.9 311.4 1680.4 132.4 2318.4 139.2 1617.3 173.6 3733.2 233.6
1967 7509.5 338.2 1384.6 97.8 2325.5 136.2 1593.7 165.7 4491.5 305.7
1968 7089.2 340.8 1949.0 213.9 2298.6 156.1 1430.9 146.6 3462.5 389.1
1969 7531.6 280.2 1573.4 100.2 2941.4 168.6 1491.0 103.5 4138.6 239.5
1970 9985.9 617.2 1608.1 123.5 3469.9 318.5 2182.5 137.7 4861.8 372.3
1971 9416.4 459.5 1605.6 123.0 3272.9 186.2 1889.3 132.9 4610.2 322.8
1972 9265.5 363.9 1622.9 120.1 3200.1 194.1 1948.2 185.8 4278.5 230.5
1973 8079.2 377.5 1245.6 90.3 2877.9 197.4 1949.2 131.9 3332.5 220.3
1974 6880.2 351.8 1592.4 128.2 2672.0 159.3 1864.5 131.2 4976.2 394.6
1975 7726.9 344.1 1643.9 109.0 2778.3 192.0 1664.8 148.1 5885.4 337.4
1976 7933.6 337.4 1244.8 85.7 2505.2 152.7 1547.5 134.0 4744.7 294.5
1977 7397.1 381.8 1299.0 126.4 2575.1 185.9 1285.8 87.9 4462.8 328.4
1978 7425.0 307.0 1558.0 92.2 3282.4 208.0 2174.2 219.1 4498.6 293.3
1979 7883.4 327.0 1757.9 121.0 3106.5 198.2 2071.7 198.5 4875.9 297.6
1980 7706.5 307.2 1392.9 98.8 3595.5 213.2 2049.9 140.7 4895.1 295.6
1981 6409.7 308.4 1395.4 120.0 2946.0 173.0 1910.5 141.7 3720.6 242.1
1982 6408.5 302.2 1633.8 126.2 2458.7 167.3 1535.7 140.2 3657.6 203.7
1983 6456.0 286.9 1519.2 144.3 2636.2 181.4 1875.0 148.0 3366.5 197.2
1984 5415.3 258.4 1515.0 125.0 3002.2 174.2 1408.2 91.5 3979.3 267.6
1985 4960.9 234.7 1303.0 98.2 2050.7 143.7 1475.4 100.3 3502.4 246.3
1986 6124.2 241.6 1547.1 107.5 1736.5 109.9 1674.9 136.1 4478.8 237.1
1987 5789.8 217.9 1305.6 97.1 2012.5 134.3 2006.2 180.4 3528.7 220.2
1988 6369.3 310.3 1349.9 121.1 2211.1 139.1 2060.8 188.3 4011.1 290.4
1989 5645.4 244.1 1414.6 106.6 1972.9 106.0 1841.7 166.4 3125.3 229.8
1990 5452.4 238.6 1672.1 135.8 1860.1 108.3 1789.5 172.7 2776.4 178.7
1991 5444.6 205.6 1583.7 111.8 2254.0 139.5 1557.8 111.3 3763.7 270.8
1992 5976.1 241.0 2032.8 143.4 2208.4 131.9 1773.1 123.7 4333.1 263.2
1993 5708.3 208.9 1755.2 107.9 2053.0 109.3 1694.5 112.7 3192.9 205.6
1994 6980.1 282.8 2318.3 145.2 2382.2 130.3 2108.4 152.2 4616.2 259.2
1995 8269.4 287.5 2835.7 187.5 2614.5 136.3 2300.6 140.3 5140.0 253.3
1996 7941.3 262.9 2984.0 152.5 2271.7 125.4 2499.5 153.4 6407.4 353.9
1997 9939.7 308.5 3897.2 264.9 3117.6 161.6 2506.6 142.5 6124.3 330.7
1998 9640.4 301.6 3742.2 205.6 2857.7 145.3 2087.3 138.9 6398.8 332.3
1999 10805.7 344.5 3235.5 163.8 2920.1 185.5 2631.0 174.6 7149.5 364.5
2000 9470.2 290.2 3158.4 200.7 2733.1 138.8 3193.5 200.1 7431.4 425.0
2001 7904.0 226.9 2679.2 136.1 2493.5 149.6 2508.7 156.4 5757.0 288.8
2002 7503.7 246.5 2235.4 135.4 2334.4 137.9 2333.5 143.8 4206.5 227.9
2003 7949.7 267.3 2549.0 169.9 2551.4 156.9 2678.5 199.7 5518.2 312.7
2004 7425.3 282.0 2589.6 165.6 1981.3 114.9 2460.8 145.2 4073.0 238.0
2005 6755.3 280.8 2179.1 131.0 2225.1 139.2 2156.9 125.8 4585.5 236.3
2006 7276.5 223.7 2824.7 174.2 2171.2 115.7 2587.2 155.3 5859.6 303.5
18
Appendix A (continued).
Northern shoveler Northern pintail Redhead Canvasback Scaup
Year Nˆ
E Sˆ Nˆ
E Sˆ Nˆ
E Sˆ Nˆ
E Sˆ Nˆ
SˆE
1955 1642.8 218.7 9775.1 656.1 539.9 98.9 589.3 87.8 5620.1 582.1
1956 1781.4 196.4 10372.8 694.4 757.3 119.3 698.5 93.3 5994.1 434.0
1957 1476.1 181.8 6606.9 493.4 509.1 95.7 626.1 94.7 5766.9 411.7
1958 1383.8 185.1 6037.9 447.9 457.1 66.2 746.8 96.1 5350.4 355.1
1959 1577.6 301.1 5872.7 371.6 498.8 55.5 488.7 50.6 7037.6 492.3
1960 1824.5 130.1 5722.2 323.2 497.8 67.0 605.7 82.4 4868.6 362.5
1961 1383.0 166.5 4218.2 496.2 323.3 38.8 435.3 65.7 5380.0 442.2
1962 1269.0 113.9 3623.5 243.1 507.5 60.0 360.2 43.8 5286.1 426.4
1963 1398.4 143.8 3846.0 255.6 413.4 61.9 506.2 74.9 5438.4 357.9
1964 1718.3 240.3 3291.2 239.4 528.1 67.3 643.6 126.9 5131.8 386.1
1965 1423.7 114.1 3591.9 221.9 599.3 77.7 522.1 52.8 4640.0 411.2
1966 2147.0 163.9 4811.9 265.6 713.1 77.6 663.1 78.0 4439.2 356.2
1967 2314.7 154.6 5277.7 341.9 735.7 79.0 502.6 45.4 4927.7 456.1
1968 1684.5 176.8 3489.4 244.6 499.4 53.6 563.7 101.3 4412.7 351.8
1969 2156.8 117.2 5903.9 296.2 633.2 53.6 503.5 53.7 5139.8 378.5
1970 2230.4 117.4 6392.0 396.7 622.3 64.3 580.1 90.4 5662.5 391.4
1971 2011.4 122.7 5847.2 368.1 534.4 57.0 450.7 55.2 5143.3 333.8
1972 2466.5 182.8 6979.0 364.5 550.9 49.4 425.9 46.0 7997.0 718.0
1973 1619.0 112.2 4356.2 267.0 500.8 57.7 620.5 89.1 6257.4 523.1
1974 2011.3 129.9 6598.2 345.8 626.3 70.8 512.8 56.8 5780.5 409.8
1975 1980.8 106.7 5900.4 267.3 831.9 93.5 595.1 56.1 6460.0 486.0
1976 1748.1 106.9 5475.6 299.2 665.9 66.3 614.4 70.1 5818.7 348.7
1977 1451.8 82.1 3926.1 246.8 634.0 79.9 664.0 74.9 6260.2 362.8
1978 1975.3 115.6 5108.2 267.8 724.6 62.2 373.2 41.5 5984.4 403.0
1979 2406.5 135.6 5376.1 274.4 697.5 63.8 582.0 59.8 7657.9 548.6
1980 1908.2 119.9 4508.1 228.6 728.4 116.7 734.6 83.8 6381.7 421.2
1981 2333.6 177.4 3479.5 260.5 594.9 62.0 620.8 59.1 5990.9 414.2
1982 2147.6 121.7 3708.8 226.6 616.9 74.2 513.3 50.9 5532.0 380.9
1983 1875.7 105.3 3510.6 178.1 711.9 83.3 526.6 58.9 7173.8 494.9
1984 1618.2 91.9 2964.8 166.8 671.3 72.0 530.1 60.1 7024.3 484.7
1985 1702.1 125.7 2515.5 143.0 578.2 67.1 375.9 42.9 5098.0 333.1
1986 2128.2 112.0 2739.7 152.1 559.6 60.5 438.3 41.5 5235.3 355.5
1987 1950.2 118.4 2628.3 159.4 502.4 54.9 450.1 77.9 4862.7 303.8
1988 1680.9 210.4 2005.5 164.0 441.9 66.2 435.0 40.2 4671.4 309.5
1989 1538.3 95.9 2111.9 181.3 510.7 58.5 477.4 48.4 4342.1 291.3
1990 1759.3 118.6 2256.6 183.3 480.9 48.2 539.3 60.3 4293.1 264.9
1991 1716.2 104.6 1803.4 131.3 445.6 42.1 491.2 66.4 5254.9 364.9
1992 1954.4 132.1 2098.1 161.0 595.6 69.7 481.5 97.3 4639.2 291.9
1993 2046.5 114.3 2053.4 124.2 485.4 53.1 472.1 67.6 4080.1 249.4
1994 2912.0 141.4 2972.3 188.0 653.5 66.7 525.6 71.1 4529.0 253.6
1995 2854.9 150.3 2757.9 177.6 888.5 90.6 770.6 92.2 4446.4 277.6
1996 3449.0 165.7 2735.9 147.5 834.2 83.1 848.5 118.3 4217.4 234.5
1997 4120.4 194.0 3558.0 194.2 918.3 77.2 688.8 57.2 4112.3 224.2
1998 3183.2 156.5 2520.6 136.8 1005.1 122.9 685.9 63.8 3471.9 191.2
1999 3889.5 202.1 3057.9 230.5 973.4 69.5 716.0 79.1 4411.7 227.9
2000 3520.7 197.9 2907.6 170.5 926.3 78.1 706.8 81.0 4026.3 205.3
2001 3313.5 166.8 3296.0 266.6 712.0 70.2 579.8 52.7 3694.0 214.9
2002 2318.2 125.6 1789.7 125.2 564.8 69.0 486.6 43.8 3524.1 210.3
2003 3619.6 221.4 2558.2 174.8 636.8 56.6 557.6 48.0 3734.4 225.5
2004 2810.4 163.9 2184.6 155.2 605.3 51.5 617.2 64.6 3807.2 202.3
2005 3591.5 178.6 2560.5 146.8 592.3 51.7 520.6 52.9 3386.9 196.4
2006 3680.2 236.5 3386.4 198.7 916.3 86.1 691.0 69.6 3246.7 166.9
19