Trends in duck breeding populations, 1955-2005

              TRENDS IN DUCK BREEDING POPULATIONS, 1955-2005
Khristi A. Wilkins, Mark C. Otto, and Mark D. Koneff
U.S. Fish and Wildlife Service
Division of Migratory Bird Management
11510 American Holly Drive
Laurel, MD 20708-4002
Administrative Report – July 14, 2005
This report summarizes information about the status of duck populations and
wetland habitats during spring 2005, focusing on areas encompassed by the U.S. Fish and
Wildlife (USFWS) and Canadian Wildlife Services’ (CWS) 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. 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 31.7 ± 0.6 [SE] million birds, similar to last year’s estimate of 32.2 ± 0.6
million birds but 5% below the 1955-2004 long-term averagea. Mallard (Anas
platyrhynchos) abundance was 6.8 ± 0.3 million birds, which was 9% below last year’s
estimate of 7.4 ± 0.3 million birds and 10% below the long-term average. Blue-winged
teal (A. discors) abundance was 4.6 ± 0.2 million birds. This value was similar to last
year’s estimate of 4.1 ± 0.2 million birds and the long-term average. Of the other duck
species, gadwall (A. strepera; 2.2 ± 0.1 million) was 16% below that of 2004, while
estimates of northern pintails (A. acuta; 2.6 ± 0.1 million; +17%) and northern shovelers
(A. clypeata; 3.6 ± 0.2 million; +28%) were significantly above 2004 estimates. The
estimate for northern shovelers was 67% above the long-term average for this species, as
were estimates of gadwall (+30%) and green-winged teal (A. crecca; 2.2 ± 0.1 million;
+16%). Northern pintails remained 38% below their long-term average despite this
year’s increase in abundance. Estimates of American wigeon (A. americana; 2.2 ± 0.1
million; -15%) and scaup (Aythya affinis and A. marila combined; 3.4 ± 0.2; -35%) also
were below their respective long-term averages; the estimate for scaup was a record low.
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.
50 Years & Still Counting
Abundances of redheads (A. americana) and canvasbacks (A. valisineria) were
unchanged from last year’s counts and long-term averages.
Habitat conditions at the onset of the survey in May were variable, with some
areas improved from last year and others remaining or becoming increasingly dry.
Habitat on the U.S. prairies was in fair to poor condition due to a dry fall, winter, and
early spring and warm winter temperatures. Nesting habitat was particularly poor in
South Dakota because of below average precipitation resulting in degraded wetland
conditions and increased tilling and grazing of wetland margins. Birds may have
overflown the state for wetter conditions to the north. Water levels and upland nesting
cover were relatively better in North Dakota and eastern Montana and wetland conditions
in these regions improved markedly during June, with the onset of well-above average
precipitation amounts. The 2005 pond estimate for north-central U.S. (1.5 ± 0.1 million)
was similar to last year’s estimate (Fig. 2).
The prairies of southern Alberta and southwestern Saskatchewan were also quite
dry in May. The U.S. and Canadian prairies received substantial rain in late May and
during the entire month of June that recharged wetlands and encouraged growth of
vegetation. While this improved habitat quality on the Prairies, it probably came too late
to benefit early-nesting species or prevent overflight. This heavy rain likely benefited
late nesting species and renesting efforts.
In contrast, the Canadian Parklands were much improved compared to last year,
due to a combination of several years of improving nesting cover and above-normal
precipitation last fall and winter. These areas were in good-to-excellent condition.
Record high levels of rain flooded the lower elevation prairie areas of central Manitoba
during April to date, producing fair or poor nesting conditions for breeding waterfowl.
Overall, pond counts in the Canadian prairies and the Canadian and U.S. prairies
combined increased over last year. The estimate of ponds in Prairie Canada was 3.9 ±
0.2 million. This was a 56% increase relative to last year’s estimate of 2.5 ± 0.1 million
ponds and 17% higher than the long-term average of 3.3 ± 0.3 million ponds. The total
pond estimate (Prairie Canada and the U.S. combined) was 5.4 ± 0.2 million ponds. This
was 37% greater than last year’s estimate of 3.9 ± 0.2 million ponds and 12% higher than
the long-term average of 4.8 ±0.1 million ponds.
Portions of Northern Manitoba and Northern Saskatchewan also experienced
flooding, resulting in only fair conditions for breeding waterfowl. By contrast, dry
conditions in parts of the Northwest Territories and Northern Alberta made for low water
levels in lakes and ponds and the complete drying of some wetlands. Therefore, habitat
was also classified as fair in these areas. However, most of the Northwest Territories was
in good condition due to adequate water and a timely spring break up that made habitat
available to early-nesting species. Alaska was in mostly excellent condition, with an
early spring and good water, except for a few flooded river areas and the North Slope
where spring was late.
2
In the Eastern survey area (strata 51-72), biologists reported that habitat
conditions were good due to adequate water and relatively mild spring temperatures. The
exceptions were the coast of Maine and the Maritimes, where May temperatures were
cool and some flooding occurred along the coast and major rivers. Also, below-normal
precipitation left some habitats in fair to poor condition in southern Ontario. However,
precipitation in southern Ontario after survey completion improved habitat conditions in
the region. Population estimates of four species were below 2004 levels as determined
by non-overlap of Bayesian 95% credibility levels. These species were American black
ducks (Anas rubripes; 0.8 million; -24%), mallards (0.4 million; -36%), mergansers
(common Mergus merganser, red-breasted M. serrator, and hooded Lophodytes
cucullatus; all 3 species pooled 0.8 million; -25%), and green-winged teal (0.4 million;
-46%). All species were similar to 1999-2004 averages.
In 2005, the USFWS and CWS took initial steps toward the integration of several
previously-independent waterfowl surveys of eastern North America. Specifically, new
analytical methods were used to generate composite estimates from USFWS and CWS
survey data, total indicated bird definitions for American black ducks were modified to
provide a common index across the surveys, and adjustments were made to the
geographic stratification in eastern North America. For these reasons, population
estimates presented in this report for the Eastern survey area are not directly comparable
with estimates presented in previous reports. Additionally, composite estimates are
presently available only for 1999-2005. In future reports, composite estimates will be
presented for a longer time-span. Changes in methods and results will be presented in
greater detail in the 2005 Waterfowl Status Report. We anticipate that composite
estimates for the Eastern survey area will change in the coming years as the USFWS and
CWS refine the integrated survey design and analytical methods.
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 D. Groves
Northern Alberta, Northeastern British Columbia, and Northwest Territories (Strata 13-18, 20,
and 77): C. Ferguson and J. Allen
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, N. Clements a,
J. Going a, R. Hunka c, T. Mathews c, I. McFarlane c, B. Peers c, R. Russell b, J.
Spenst c, S. Tucker a, and E. Whelan a
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. Leafloor a, P. Rakowski a,
M. Schuster a, K. Dufour a, C. Downie a, P. Nieman a, N. Weibe a, C. Wilkinson a,
A. Williams c, J. Caswell a, F. Baldwin a, C. Meuckon a, L. Beaudoin a, and S.
Lawson c
Southern Manitoba (Strata 25 and 36-40):
Air R. King and S. Frazer
Ground D. Caswell a, J. Leafloor a, P. Rakowski a, M. Schuster a, G. Ball b, F. Baldwin a,
L. Beaudoin a, J. Caswell a, J. Galbraith a, S. Lawson c, and C. Meuckon a
Montana and Western Dakotas (Strata 41-44):
Air R. Bentley and H. Woods
Ground K. Richkus and T. Wilkendorf
Eastern Dakotas (Strata 45-49):
Air J. Solberg and M. Rich
Ground P. Garrettson, K. Kruse, and E. Lang
Central Quebec (Strata 68 and 69):
Air J. Wortham, D. Fronczak, and H. Obrecht
Helicopter D. Bordage a, C. Lepage a, S. Orichefsky a, G. Gagnon d, M. Samson d, D. Dubé d,
J. Vallières d
New York, Eastern Ontario, Western James Bay Lowlands, and Southern Quebec
(Strata 52-58):
Air M. Koneff, M. Jones, and R. Raftovich
Helicopter K. Ross a, D. McNichol a, D. Fillman a, B. Collins a, and G. Ertel d
4
Central and Western Ontario (Strata 50 and 51):
Air K. Bollinger and G. Foulks
Helicopter K. Ross a, D. McNichol a, D. Fillman a, B. Collins a, and G. Ertel d,
Maine and Maritimes (Strata 62-67):
Air J. Bidwell, M. Drut, and J. Goldsberry d
Helicopter S. Gilliland a, P. Ryan a, R. Hicks a, E. Loeder b,D. Bursey d, G. Boyd d, J. Myra d,
M. Paddon d
Habitat information was provided by U.S. Fish and Wildlife Service and Canadian Wildlife
Service biologists.
Analysis of Eastern survey data by John R. Sauer, U.S. Geological Survey.
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 2004 Change from LTA
Region 2005 2004 % P LTA a % P
Alaska-Yukon Territory
– Old Crow Flats 5,114 5,456 -6 0.194 3,519 +45 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 4,713 5,882 -20 0.001 7,202 -35 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 3,223 4,085 -21 0.007 3,564 -10 0.099
S. Alberta 3,178 2,499 +27 0.002 4,305 -26 <0.001
S. Saskatchewan 7,967 5,783 +38 <0.001 7,336 +9 0.024
S. Manitoba 1,627 1,474 +10 0.172 1,542 +5 0.287
Montana and western Dakotas 1,290 1,615 -20 0.006 1,620 -20 <0.001
Eastern Dakotas 4,623 5,370 -14 0.022 4,193 +10 0.067
Total b 31,735 32,164 -1 0.593 33,281 -5 0.006
a Long-term average, 1955-2004.
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 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 703 811 -13 0.199 350 +101 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 533 776 -31 0.025 1,097 -51 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 937 1,283 -27 0.143 1,163 -19 0.165
S. Alberta 671 600 +12 0.460 1,107 -39 <0.001
S. Saskatchewan 1,729 1,609 +7 0.515 2,079 -17 0.007
S. Manitoba 455 393 +16 0.194 377 +21 0.054
Montana and western Dakotas 387 495 -22 0.160 502 -23 0.017
Eastern Dakotas 1,340 1,456 -8 0.520 836 +60 <0.001
Total 6,755 7,425 -9 0.092 7,510 -10 0.008
7
Table 3. Gadwall breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 3 2 +42 0.734 2 +43 0.705
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 77 138 -44 0.083 46 +66 0.050
N. Saskatchewan- N. Manitoba
- W. Ontario 19 22 -16 0.772 28 -32 0.133
S. Alberta 338 290 +17 0.492 308 +10 0.612
S. Saskatchewan 723 752 -4 0.847 553 +31 0.052
S. Manitoba 120 148 -18 0.362 65 +84 <0.001
Montana and western Dakotas 187 205 -9 0.614 194 -4 0.797
Eastern Dakotas 712 1,033 -31 0.006 486 +46 0.001
Total 2,179 2,590 -16 0.052 1,683 +30 <0.001
Table 4. American wigeon breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 873 897 -3 0.790 504 +73 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 583 565 +3 0.889 919 -36 0.002
N. Saskatchewan- N. Manitoba
- W. Ontario 174 149 +17 0.568 254 -31 0.013
S. Alberta 125 117 +8 0.728 300 -58 <0.001
S. Saskatchewan 294 128 +130 0.002 428 -31 0.006
S. Manitoba 34 3 +893 0.002 62 -45 0.006
Montana and western Dakotas 67 66 +2 0.926 110 -39 <0.001
Eastern Dakotas 73 56 +30 0.405 48 +53 0.114
Total 2,225 1,981 +12 0.177 2,624 -15 0.005
8
Table 5. Green-winged teal breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 713 819 -13 0.289 351 +103 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 437 835 -48 0.002 759 -42 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 310 375 -17 0.262 195 +59 0.002
S. Alberta 159 98 +61 0.138 195 -18 0.291
S. Saskatchewan 359 124 +189 <0.001 227 +58 0.027
S. Manitoba 55 27 +103 0.007 52 +7 0.686
Montana and western Dakotas 83 104 -20 0.395 39 +113 0.008
Eastern Dakotas 42 79 -47 0.079 45 -8 0.742
Total 2,157 2,461 -12 0.114 1,861 +16 0.021
Table 6. Blue-winged teal breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 3 2 +25 0.876 1 +105 0.626
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 247 401 -38 0.116 271 -9 0.704
N. Saskatchewan- N. Manitoba
- W. Ontario 139 60 +130 0.102 268 -48 0.007
S. Alberta 649 360 +80 0.009 608 +7 0.665
S. Saskatchewan 1,597 1,155 +38 0.026 1,210 +32 0.002
S. Manitoba 339 282 +20 0.206 383 -12 0.207
Montana and western Dakotas 286 320 -10 0.508 263 +9 0.467
Eastern Dakotas 1,325 1,493 -11 0.427 1,496 -11 0.275
Total 4,586 4,073 +13 0.126 4,499 +2 0.720
9
Table 7. Northern shoveler breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 666 643 +4 0.806 259 +158 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 213 247 -14 0.554 213 0 0.992
N. Saskatchewan- N. Manitoba
- W. Ontario 29 33 -13 0.683 43 -34 0.016
S. Alberta 548 385 +42 0.133 356 +54 0.018
S. Saskatchewan 1,314 784 +68 0.001 634 +107 <0.001
S. Manitoba 211 143 +47 0.176 105 +100 0.004
Montana and western Dakotas 148 200 -26 0.204 149 -1 0.959
Eastern Dakotas 464 377 +23 0.212 388 +19 0.170
Total 3,591 2,810 +28 0.001 2,149 +67 <0.001
Table 8. Northern pintail breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 905 927 -2 0.856 913 -1 0.939
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 108 193 -44 0.073 384 -72 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 8 10 -18 0.672 42 -80 <0.001
S. Alberta 282 161 +75 0.049 730 -61 <0.001
S. Saskatchewan 858 474 +81 0.009 1,225 -30 <0.001
S. Manitoba 68 40 +71 0.042 113 -40 <0.001
Montana and western Dakotas 75 132 -43 0.031 273 -73 <0.001
Eastern Dakotas 256 247 +4 0.860 463 -45 <0.001
Total 2,561 2,185 +17 0.079 4,142 -38 <0.001
10
Table 9. Redhead breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats <1 2 -91 0.044 1 -84 <0.001
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 49 73 -33 0.304 38 +30 0.530
N. Saskatchewan- N. Manitoba
- W. Ontario 13 31 -57 0.136 28 -53 <0.001
S. Alberta 91 79 +16 0.648 117 -22 0.170
S. Saskatchewan 226 131 +72 0.02 189 +19 0.251
S. Manitoba 98 102 -4 0.900 71 +37 0.338
Montana and western Dakotas 3 25 -89 0.102 10 -70 0.002
Eastern Dakotas 112 161 -31 0.102 170 -34 0.002
Total 592 605 -2 0.858 625 -5 0.536
Table 10. Canvasback breeding population estimates (in thousands) for regions in the traditional survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 95 161 -41 0.207 91 +4 0.887
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 98 109 -11 0.768 72 +35 0.416
N. Saskatchewan- N. Manitoba
- W. Ontario 39 50 -21 0.578 56 -30 0.253
S. Alberta 43 50 -15 0.758 64 -33 0.104
S. Saskatchewan 162 121 +34 0.181 183 -11 0.425
S. Manitoba 48 70 -32 0.344 56 -15 0.518
Montana and western Dakotas 5 12 -60 0.046 8 -39 0.095
Eastern Dakotas 31 44 -28 0.275 33 -5 0.817
Total 521 617 -16 0.247 563 -8 0.433
11
Table 11. Scaup (greater and lesser combined) breeding population estimates (in thousands) for regions in the traditional
survey area.
Change from 2004 Change from LTA
Region 2005 2004 % P LTA % P
Alaska-Yukon Territory
– Old Crow Flats 961 982 -2 0.865 914 +5 0.593
C. & N. Alberta – N.E. British Columbia
- Northwest Territories 1,361 1,624 -16 0.232 2,653 -49 <0.001
N. Saskatchewan- N. Manitoba
- W. Ontario 349 582 -40 <0.001 592 -41 <0.001
S. Alberta 127 124 +2 0.948 358 -65 <0.001
S. Saskatchewan 381 185 +106 0.008 417 -9 0.595
S. Manitoba 60 31 +91 0.019 137 -56 <0.001
Montana and western Dakotas 16 28 -41 0.309 54 -70 <0.001
Eastern Dakotas 132 251 -47 0.034 96 +37 0.162
Total 3,387 3,807 -11 0.136 5,220 -35 <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 2004 Change from LTA
Survey Area 2005 2004 % P LTAa % P
Prairie Canada
S. Alberta 750 511 +47 0.007 721 +4 0.689
S. Saskatchewan 2415 1,461 +65 <0.001 1,953 +24 0.009
S. Manitoba 755 541 +40 0.001 671 +13 0.101
Subtotal 3,921 2,513 +56 <0.001 3,346 +17 0.004
Northcentral U.S.
Montana and western Dakotas 663 597 +11 0.354 524 +27 0.016
Eastern Dakotas 798 810 -1 0.913 1,000 -20 <0.001
Subtotal 1,461 1,407 +4 0.678 1,524 -4 0.440
Grand Total 5,381 3,920 +37 <0.001 4,813 +12 0.008
aLong-term average. Prairie and parkland Canada, 1961-2004; northcentral U.S. and Grand Total, 1974-2004.
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 and parkland Canada and the
northcentral U.S.
13
Table 13. Duck breeding population estimates (median, in thousands) for 6 species in the eastern survey area.
Species 2005 2004 % Change from
2004 Average a % Change from
average
Mergansers (common, red-breasted, & hooded) 753 995 -25 b 825 -9
Mallard 412 646 -36 b 546 -25
American black duck 827 1093 -24 b 1002 -18
Green-winged teal 423 776 -46 b 521 -19
Ring-necked duck 883 1257 -30 1032 -14
Goldeneye (common & Barrow’s) 715 748 -5 901 -21
a Average for 1999-2004.
b Significant (P<0.05) determined by non-overlap of Bayesian credibility intervals.
14
Breeding Waterfowl Habitat Conditions, May 2005
Excellent
Good
Figure 3. Breeding waterfowl habitat conditions during the 2005 Waterfowl Breeding Population and Habitat Survey, as judged by U.S. Fish
and Wildlife Service Flyway Biologists. Changes in conditions due to additional precipitation following completion of survey efforts are
described in the narrative.
Poor
Fair
Good
Excellent
15
Figure 4. Breeding waterfowl habitat conditions during the 2004 Waterfowl Breeding Population and Habitat Survey, as judged by U.S. Fish
and Wildlife Service Flyway Biologists.
Poor
Fair
Good
Excellent
16
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
17
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
18
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
19
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
20
Appendix B. Breeding population estimates (median, in thousands) and 95% credibility intervals (CI) for 6 species of ducks in the eastern survey area, 1999-2005.
Mergansers Mallard American black duck Green-winged teal Ring-necked duck Goldeneyes
Year Nˆ
CI Nˆ
CI Nˆ
CI Nˆ
CI Nˆ
CI Nˆ
CI
1999 602.7 (422 - 951) 554.1 (369 - 901) 1,018.0 (732 - 1,362) 627.6 (329, 1,613) 905.3 (583 - 1,560) 821.1 (449 - 2,075)
2000 653.3 (462 - 1,007) 443.8 (306 - 656) 885.9 (638 - 1,206) 347.9 (201, 771) 1,342.0 (765 - 3,241) 778.7 (424 - 2,048)
2001 636.4 (440 - 1,039) 465.0 (321 - 704) 864.9 (603 - 1,206) 265.9 (136, 761) 838.6 (562 - 1,361) 1,118.0 (566 - 3,155)
2002 1,170.0 (809 - 1,930) 517.5 (355 - 769) 1,174.0 (770 - 1,708) 588.8 (254, 2,350) 834.9 (590 - 1,267) 970.3 (507 - 2,656)
2003 890.8 (622 - 1,414) 648.1 (437 - 1,122) 976.2 (675 - 1,389) 521.1 (262, 1,571) 1,012.0 (697 - 1,550) 968.4 (495 - 2,747)
2004 995.0 (704 - 1,547) 645.5 (438 - 1,114) 1,093.0 (739 - 1,571) 775.7 (344, 2,629) 1,257.0 (839 - 2,090) 747.8 (440 - 1,587)
2005 752.8 (529 - 1,173) 411.7 (281 - 635) 826.5 (582 - 1,137) 422.9 (195, 1,256) 883.1 (572 - 1,691) 714.7 (371 - 2,078)
21