Trends in duck breeding populations, 1955-2004

              TRENDS IN DUCK BREEDING POPULATIONS, 1955-2004
K. A. Wilkins and M. C. Otto
U.S. Fish and Wildlife Service
Division of Migratory Bird Management
11500 American Holly Drive
Laurel, MD 20708-4016
Administrative Reporta – July 8, 2004
This report summarizes information about the status of duck populations and
wetland habitats during spring 2004, focusing on areas encompassed by the U.S. Fish and
Wildlife and Canadian Wildlife Services’ Waterfowl Breeding Population and Habitat
Survey. The estimates do not include information from surveys conducted by State or
Provincial agencies. In the traditional survey area, which includes strata 1-18, 20-50, and
75-77 (Fig. 2), 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 32.2 ± 0.6
[SE] million birds, 11% below (P < 0.001) last year’s estimate of 36.2 ± 0.7 million birds
and 3% below the 1955-2003 long-term average (P = 0.053). Mallard (Anas
platyrhynchos) abundance was 7.4 ± 0.3 million birds, which was similar to last year’s
estimate of 7.9 ± 0.3 million birds (P = 0.177) and the long-term average (P = 0.762).
Blue-winged teal (A. discors) abundance was 4.1 ± 0.2 million birds. This value was
26% below last year’s estimate of 5.5 ± 0.3 million birds (P < 0.001) and 10% below the
long-term average (P = 0.073). Of the other duck species, only estimates of northern
shovelers (A. clypeata; 2.8 ± 0.2 million) and American wigeon (A. americana; 2.0 ± 0.1
million) were significantly different from 2003 estimates (P < 0.003), and both were 22%
below 2003 estimates. Compared to the long-term averages, gadwall (A. strepera; 2.6 ±
0.2 million; +56%), green-winged teal (A. crecca; 2.5 ± 0.1 million; +33%) and shovelers
(+32%) were above their 1955-2003 averages (P < 0.001), as they were in 2003. In
2004, northern pintails (A. acuta; 2.2 ± 0.2 million; -48%) and scaup (Aythya affinis and
A. marila combined; 3.8 ± 0.2 million; -27%) remained well below their long-term
averages (P < 0.001). Wigeon also were below their long-term average in 2004 (-25%; P
< 0.001). Estimates of redheads (A. americana) and canvasbacks (A. valisineria) were
unchanged from their previous year and long-term averages (P ≥ 0.396).
a This report is intended for administrative use only and is not for publication without the permission of the
Director, U.S. Fish and Wildlife Service.
The eastern survey area is comprised of strata 51-56 and 62-69 (Fig. 2). The 2004
total-duck estimate for this area was 3.9 ± 0.3 million birds. This estimate was similar to
that of last year and the 1996-2003 average (P 􀂕􉔠 0.102). Estimates for most individual
species were similar to last year and to 1996-2003 averages. Only numbers of ring-necked
ducks (A. collaris) were significantly different from 2003 estimates, increasing by
67% to 0.7 ± 0.2 million birds (P = 0.095). Wigeon (0.1 ± 0.1 million; -61%) and
goldeneye (Bucephala clangula and B. islandica combined; 0.4 ± 0.1 million; -42%)
were below their 1996-2003 averages (P 􀁤􆐠 0.052). All other species were similar to 2003
estimates and 1996-2003 averages.
Most of the U.S. and Canadian prairies were much drier in May 2004 compared to
May 2003. Unfortunately, good water conditions in the short-grass prairie of southern
Alberta and Saskatchewan seen last year did not carry over to this year, and habitat in
these areas deteriorated from good last year to fair or poor this year. Habitat conditions
in Manitoba ranged from poor in the east to good in the west, similar to conditions
observed last year. The Dakotas have experienced a slow drying trend over the past few
years, and much of eastern South Dakota was in poor condition. Habitat conditions in
North Dakota improved in northern regions. Eastern Montana was a mosaic of habitat
conditions ranging from poor to good. Although many areas of the southern prairies
received considerable snowfall during the winter and spring of 2003-2004, including a
late spring snowstorm, the snowmelt was absorbed by the parched ground. As a
consequence, fewer ponds were counted in the prairies this spring. The estimate of May
ponds for the northcentral U.S. and Prairie Canada combined was 3.9 ± 0.2 million. This
was 24% lower than last year (P < 0.001) and 19% below the long-term average (P <
0.001). Numbers of ponds in Canada (2.5 ± 0.1 million) and the U.S. (1.4 ± 0.1 million)
both were below 2003 estimates (-29% in Canada and -16% in the U.S.; P 􀁤􆐠 0.033) and
the number of Canadian ponds was 25% below the long-term average (P < 0.001).
Snowy and cold conditions present during May probably adversely impacted early
nesting species and young broods.
This year, the Northwest Territories, Northern Alberta, Northern Saskatchewan,
and Northern Manitoba were exceptionally late in thawing; birds that over-flew the dry
prairies encountered winter-like conditions and nesting may have been curtailed. This is
especially true for early nesting species such as mallards and pintails. Unlike the
northern areas of Canada, Alaska had excellent habitat conditions for breeding waterfowl
this spring. Areas south of Alaska’s Brooks Range experienced a widespread, record-setting
early spring breakup, and only minor flooding.
Breeding habitat conditions were generally good to excellent in the eastern U.S.
and Canada. Although spring was late in most areas, biologists believed that nesting was
not significantly affected because of abundant spring rain and mild temperatures.
Next year is the 50th anniversary of the May Waterfowl Breeding Population and Habitat survey.
2
The data in this report were contributed by the following individuals:
Alaska, Yukon Territory, and Old Crow Flats (Strata 1-12): B. Conant and D. Groves
Northern Alberta, Northeastern British Columbia, and Northwest Territories (Strata 13-18, 20, and 77):
C. Ferguson and W. Mullins
Northern Saskatchewan and Northern Manitoba (Strata 21-24): F. Roetker and P. Stinson
Southern and Central Alberta (Strata 26-29, 75, and 76):
Air E. Buelna Huggins and C. Pyle
Ground P. Pryor a, K. Froggatt b, S. Barry a, E. Hofman b, C. Procter a, M. Barr c, N. Clements a, N.
Fontaine c, J. Going a, R. Hunka c, T. Mathews c, B. Peers c, R. Russell b, J. Spenst c, and K.
Zimmer a
Southern Saskatchewan (Strata 30-35):
Air P. Thorpe, T. Lewis, R. King, and C. Reighn
Ground D. Nieman a, J. Smith a, K. Warner a, K. Dufour a, C. Wilkinson a, K. Cochrane a, P.
Nieman a, A. Williams c, M. Schuster a, D. Caswell a, J. Leafloor a, P. Rakowski a, F.
Baldwin a, R. Bazin a, J. Caswell a, J. Galbraith a, C. Lindgren c, C. Meuckon a, and N.
Wiebe a
Southern Manitoba (Strata 25 and 36-40):
Air R. King and C. Reighn
Ground M. Schuster a, D. Caswell a, J. Leafloor a, P. Rakowski a, F. Baldwin a, G. Ball b,
J. Caswell a, J. Galbraith a, C. Lindgren c, C. Meuckon a, and N. Wiebe a
Montana and Western Dakotas (Strata 41-44):
Air J. Voelzer and R. Bentley
Ground K. Richkus and D. D’Auria
Eastern Dakotas (Strata 45-49):
Air J. Solberg and M. Rich
Ground P. Garrettson, A. Araya, K. Kruse, and T. Thorn
Central Quebec (Strata 68 and 69):
Air J. Wortham, D. Fronczak, and J. Goldsberry d
Helicopter D. Holtby b, R. Raftovich, and G. Boomer
New York, Eastern Ontario, and Southern Quebec (Strata 52-56): M. Koneff, D. Forsell, and M. Jones
Central and Western Ontario (Strata 50 and 51): K. Bollinger and W. Butler
Maine and Maritimes (Strata 62-67): J. Bidwell and M. Drut
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
3
4
Table 1. Estimated number (in thousands) of May ponds in portions of Prairie Canada and the northcentral U.S.
Change from 2003 Change from LTA
Survey Area 2003 2004 % P LTAa % P
Prairie Canada
S. Alberta 888 511 -43 <0.001 726 -30 <0.001
S. Saskatchewan 2143 1461 -32 <0.001 1964 -26 <0.001
S. Manitoba 491 541 +10 0.280 674 -20 <0.001
Subtotal 3522 2513 -29 <0.001 3365 -25 <0.001
Northcentral U.S.
Montana and western Dakotas 480 597 +25 0.018 521 +15 0.071
Eastern Dakotas 1188 810 -32 0.001 1006 -20 0.037
Subtotal 1668 1407 -16 0.033 1528 -8 0.243
Grand Total 5190 3920 -24 <0.001 4842 -19 <0.001
aLong-term average. Prairie Canada, 1961-2003; northcentral U.S. and Grand Total, 1974-2003.
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 1. Number of ponds in May and 95% confidence intervals in Prairie Canada and the northcentral U.S.
5
Table 2. Duck breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA a % P
Alaska-Yukon Territory
– Old Crow Flats 5705 5456 -4 0.361 3480 +57 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 6461 5882 -9 0.160 7229 -19 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 3564 4085 +15 0.106 3554 +15 0.033
S. Alberta 2696 2499 -7 0.309 4342 -42 <0.001
S. Saskatchewan 9296 5783 -38 <0.001 7367 -22 <0.001
S. Manitoba 1582 1474 -7 0.354 1544 -5 0.393
Montana and western Dakotas 1731 1615 -7 0.413 1620 0 0.955
Eastern Dakotas 5190 5370 +3 0.590 4169 +29 <0.001
Total b 36225 32164 -11 <0.001 33304 -3 0.053
a Long-term average, 1955-2003.
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 3. Mallard breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 843 811 -4 0.726 341 +138 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 852 776 -9 0.502 1103 -30 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 1103 1283 +16 0.417 1161 +11 0.482
S. Alberta 627 600 -4 0.766 1118 -46 <0.001
S. Saskatchewan 2111 1609 -24 0.011 2088 -23 <0.001
S. Manitoba 505 393 -22 0.032 376 +5 0.509
Montana and western Dakotas 506 495 -2 0.891 502 -1 0.911
Eastern Dakotas 1402 1456 +4 0.727 823 +77 <0.001
Total 7950 7425 -7 0.177 7512 -1 0.762
6
Table 4. Gadwall breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 5 2 -59 0.268 2 +1 0.991
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 76 138 +82 0.066 44 +211 0.003
N. Saskatchewan- N. Manitoba
- W. Ontario 30 22 -27 0.524 28 -20 0.599
S. Alberta 241 290 +20 0.313 308 -6 0.636
S. Saskatchewan 1077 752 -30 0.071 549 +37 0.094
S. Manitoba 94 148 +57 0.075 64 +131 0.002
Montana and western Dakotas 206 205 0 0.987 194 +6 0.653
Eastern Dakotas 821 1033 +26 0.110 475 +117 <0.001
Total 2549 2590 +2 0.864 1664 +56 <0.001
Table 5. American wigeon breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 1020 897 -12 0.240 496 +81 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 850 565 -34 0.053 926 -39 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 191 149 -22 0.378 256 -42 0.001
S. Alberta 132 117 -11 0.609 304 -62 <0.001
S. Saskatchewan 219 128 -41 0.019 434 -70 <0.001
S. Manitoba 16 3 -78 <0.001 63 -95 <0.001
Montana and western Dakotas 43 66 +52 0.101 111 -41 <0.001
Eastern Dakotas 81 56 -30 0.224 48 +18 0.500
Total 2551 1981 -22 0.003 2637 -25 <0.001
7
Table 6. Green-winged teal breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 1035 819 -21 0.068 341 +140 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 767 835 +9 0.728 757 +10 0.486
N. Saskatchewan- N. Manitoba
- W. Ontario 308 375 +22 0.303 191 +96 <0.001
S. Alberta 132 98 -25 0.384 196 -50 <0.001
S. Saskatchewan 273 124 -54 0.001 229 -46 <0.001
S. Manitoba 48 27 -44 0.023 52 -48 <0.001
Montana and western Dakotas 85 104 +22 0.403 38 +177 <0.001
Eastern Dakotas 30 79 +159 0.019 45 +76 0.059
Total 2678 2461 -8 0.378 1849 +33 <0.001
Table 7. Blue-winged teal breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 3 2 -24 0.852 1 +66 0.683
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 314 401 +27 0.389 268 +49 0.087
N. Saskatchewan- N. Manitoba
- W. Ontario 182 60 -67 0.006 272 -78 <0.001
S. Alberta 323 360 +12 0.647 613 -41 <0.001
S. Saskatchewan 1918 1155 -40 0.004 1211 -5 0.717
S. Manitoba 420 282 -33 0.032 385 -27 0.001
Montana and western Dakotas 419 320 -24 0.186 262 +22 0.160
Eastern Dakotas 1939 1493 -23 0.062 1496 0 0.984
Total 5518 4073 -26 <0.001 4508 -10 0.073
8
Table 8. Northern shoveler breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 671 643 -4 0.748 251 +156 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 318 247 -23 0.168 213 +16 0.387
N. Saskatchewan- N. Manitoba
- W. Ontario 10 33 +226 0.011 44 -25 0.219
S. Alberta 448 385 -14 0.465 356 +8 0.692
S. Saskatchewan 1438 784 -45 0.003 631 +24 0.166
S. Manitoba 123 143 +16 0.604 105 +37 0.264
Montana and western Dakotas 247 200 -19 0.394 148 +35 0.142
Eastern Dakotas 365 377 +3 0.836 388 -3 0.804
Total 3620 2810 -22 0.003 2135 +32 <0.001
Table 9. Northern pintail breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 848 927 +9 0.440 913 +2 0.845
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 170 193 +14 0.613 388 -50 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 6 10 +84 0.236 42 -76 <0.001
S. Alberta 252 161 -36 0.117 742 -78 <0.001
S. Saskatchewan 993 474 -52 0.005 1241 -62 <0.001
S. Manitoba 39 40 +1 0.972 115 -65 <0.001
Montana and western Dakotas 122 132 +8 0.791 276 -52 <0.001
Eastern Dakotas 128 247 +92 0.020 467 -47 <0.001
Total 2558 2185 -15 0.110 4182 -48 <0.001
9
Table 10. Redhead breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 3 2 -21 0.813 1 +69 0.376
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 29 73 +150 0.006 37 +97 0.015
N. Saskatchewan- N. Manitoba
- W. Ontario 26 31 +19 0.774 28 +10 0.801
S. Alberta 97 79 -19 0.523 118 -33 0.065
S. Saskatchewan 271 131 -52 0.007 191 -31 0.026
S. Manitoba 71 102 +44 0.234 71 +44 0.129
Montana and western Dakotas 22 25 +13 0.845 9 +170 0.240
Eastern Dakotas 117 161 +38 0.133 170 -5 0.731
Total 637 605 -5 0.681 625 -3 0.705
Table 11. Canvasback breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 89 161 +81 0.164 90 +79 0.121
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 115 109 -5 0.873 72 +53 0.141
N. Saskatchewan- N. Manitoba
- W. Ontario 13 50 +277 0.009 56 -11 0.670
S. Alberta 70 50 -28 0.421 64 -22 0.494
S. Saskatchewan 195 121 -38 0.022 184 -34 0.001
S. Manitoba 42 70 +68 0.184 56 +26 0.474
Montana and western Dakotas 11 12 +5 0.888 8 +55 0.190
Eastern Dakotas 23 44 +93 0.059 33 +34 0.230
Total 558 617 +11 0.458 562 +10 0.396
10
Table 12. Scaup (greater and lesser combined) breeding population estimates (in thousands) for regions in the traditional
survey area.
Change from 2003 Change from LTA
Region 2003 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 970 982 +1 0.925 913 +8 0.461
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 1736 1624 -6 0.643 2673 -39 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 354 582 +64 0.004 592 -2 0.860
S. Alberta 172 124 -28 0.340 363 -66 <0.001
S. Saskatchewan 251 185 -26 0.240 422 -56 <0.001
S. Manitoba 49 31 -35 0.176 139 -77 <0.001
Montana and western Dakotas 35 28 -21 0.628 55 -50 0.009
Eastern Dakotas 167 251 +50 0.145 93 +169 0.002
Total 3734 3807 +2 0.810 5249 -27 <0.001
11
Table 13. Duck breeding population estimates (in thousands, for the 10 most abundant species) for the eastern survey area.
Change from 2003 Change from LTA
Species 2003 2004 % P Average a % P
Mergansers (common, red-breasted, & hooded) 569 668 +17 0.439 537 +24 0.264
Mallard 383 368 -4 0.853 312 +18 0.358
American black duck 533 730 +37 0.234 498 +47 0.137
American wigeon 79 27 -66 0.133 68 -61 0.004
Green-winged teal 452 554 +22 0.558 356 +56 0.123
Lesser scaup 101 81 -20 0.629 81 0 0.996
Ring-necked duck 399 668 +67 0.095 479 +39 0.225
Goldeneye (common & Barrow’s) 768 430 -44 0.191 746 -42 0.052
Bufflehead 66 44 -34 0.260 60 -27 0.183
Scoters (surf, black, & white-winged) 237 261 +10 0.822 154 +70 0.200
Total b 3635 3905 +7 0.533 3343 +17 0.102
a Average for 1996-2003.
b Includes species in table plus gadwall, northern shoveler, northern pintail, eiders, and blue-winged teal. Excludes long-tailed duck, wood duck, redhead, canvasback,
and ruddy duck.
4
2
7
1
6
11
10
9
8
12 13
14
15
17
16
18
20
26
27
21
30
22
23
24
3
77
76
75
28
29 33
32
31
35
34
36
37
40
39 38
25
41
42
45
43
46
47
44 48
49
50 51
57
54
52
55
53
68
56 62
63
64
69
65
67
66
5
Figure 2. Strata and transects for areas of the May Waterfowl Breeding Population and Habitat Survey (stratum 57 is experimental and survey counts are not included in this report).
12
Figure 3. Palmer long-term drought indices (PDI) for the contiguous U.S. and provinces of Canada for which data were available. U.S. PDI map from Weekly
Weather and Crop Bulletin - May 28, 2003 and May 29, 2004; Canadian PDI map from Environment Canada - May 2003 and May 2004.
Moderate to severe dryness
Near normal
Moderate to extreme wetness
2003 2004
13
Poor
Fair
Good
Excellent
Figure 4. Breeding waterfowl habitat conditions during May and June 2004, as judged by U.S. Fish and Wildlife Service Flyway Biologists.
14
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
15
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
16
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 N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E S�� N ˆ
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
17
Appendix A. Continued.
Northern shoveler Northern pintail Redhead Canvasback Scaup
Year N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
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
18
Appendix B. Breeding population estimates and standard errors (in thousands) for the 10 most abundant species of ducks in the eastern survey area, 1990-2004 a.
Mergansers Mallard
American
black duck
American
wigeon
Am. green-winged
teal
Lesser
scaup
Ring-necked
duck Goldeneyes Bufflehead Scoters
Year N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
E Sˆ N ˆ
SˆE
1990 157.5 48.3 208.6 47.7 160.9 33.5 31.0 22.6 47.1 8.6 135.7 56.2 92.1 28.3 73.3 22.2 99.9 22.9 1.9 1.9
1991 263.9 78.6 169.8 34.5 126.0 35.3 45.4 21.8 42.2 14.4 43.5 16.4 158.1 30.2 138.4 44.3 94.1 32.1 6.4 5.3
1992 128.1 24.3 362.2 54.1 160.3 33.1 15.4 9.3 43.8 13.9 65.6 23.2 251.6 62.3 241.0 55.2 59.0 13.7 3.0 2.3
1993 164.9 23.7 333.8 49.7 124.6 25.6 9.4 7.4 47.4 9.9 288.6 235.3 248.1 65.1 90.2 32.6 13.1 3.6 0.0 0.0
1994 358.4 91.8 238.6 28.8 116.3 20.7 18.9 9.6 169.2 24.0 81.9 31.7 163.5 62.6 55.0 17.4 33.4 14.0 18.3 9.7
1995 376.3 89.7 212.6 41.1 234.5 46.6 13.8 7.9 96.2 14.1 62.0 20.5 195.6 51.0 9.2 3.7 26.5 8.8 5.0 4.8
1996 1083.1 279.6 387.6 63.6 562.2 97.1 34.7 17.0 436.2 86.9 38.5 15.1 611.9 98.7 410.3 169.7 50.6 12.5 23.6 10.5
1997 379.1 53.0 287.6 44.8 434.5 63.1 22.5 11.2 211.5 31.3 16.7 7.2 617.6 151.1 220.6 54.8 22.3 6.7 88.9 50.2
1998 327.4 38.8 363.2 71.3 542.1 55.4 83.6 24.6 299.5 81.1 20.1 10.6 361.8 53.8 715.7 124.7 44.6 10.3 159.4 47.1
1999 290.0 39.4 280.8 39.2 488.7 51.3 121.1 45.6 422.4 62.3 44.9 20.5 453.2 76.0 920.0 167.3 70.5 20.8 47.0 17.7
2000 400.0 54.0 212.3 31.3 396.9 53.9 41.7 20.4 201.6 28.7 19.8 9.1 618.8 71.3 946.5 318.7 49.3 11.3 182.1 59.0
2001 428.7 62.8 285.7 40.8 422.0 48.8 77.5 18.2 220.3 33.5 203.5 92.2 352.8 39.6 1032.2 202.4 95.0 20.9 178.6 49.4
2002 815.2 97.9 295.1 38.1 602.8 86.1 86.6 25.5 604.1 129.0 136.1 48.2 416.0 57.8 954.9 209.2 83.6 21.2 314.4 76.4
2003 569.1 63.9 383.1 57.8 532.6 60.2 79.0 32.8 452.3 120.1 101.2 21.2 399.3 50.3 767.9 212.1 66.3 17.0 237.1 66.9
2004 668.0 110.5 367.9 58.2 729.8 154.3 27.0 11.0 553.8 125.1 81.1 35.7 667.6 152.6 429.9 147.4 43.8 11.1 260.9 81.5
a Maine estimates were included beginning in 1995. Quebec estimates were included beginning in 1996. Therefore, estimates are only comparable within year groups 1990-94, and
1996-present.
19