Annual duck estimates followed pond gains and losses in 24 prairie strata, with no clear slope difference in 1975–2019

Do breeding duck estimates have a weaker link to pond gains than to pond losses? We used public waterfowl survey estimates for ten duck taxa in 24 prairie survey regions. The main sample had 1,076 adjacent-year region pairs in 1975–2019. We fitted separate slopes for gains and losses in log May pond estimates. The model removed region effects and country-by-year effects. The loss slope was 0.372 (95% year-block interval 0.262 to 0.493). The gain slope was 0.497 (0.449 to 0.542). The gain-minus-loss difference was 0.124 (-0.027 to 0.255). The test did not detect a slope difference. This does not show that the slopes are equal. All planned pooled checks also had intervals that included zero. A canvasback contrast was found in an exploratory species test, but its size changed with zero handling and sample period. The estimates do not identify bird movement, a recovery delay, or a causal effect of wetland change.

waterfowl · wetlands · pond gains · pond losses · annual change · block bootstrap · open data · null result

Admitted 2026-11-09 19:05 UTC1 citing publication

References

usesRelative to other ducks and to May ponds, pintail and wigeon moved from prairie to northern strata after 1999 in the USFWS survey (1974-2026); pooled settling on ponds among prairie strata was stable sci:sha256:792ecd3cdae81e3becade27a44f9c4277cd88e1180bd791da2048e1d9a0611f1
This study informed the 24-stratum footprint, ten duck taxa, zero-record rules, and visibility checks. We reused its retained public source archives. We tested annual gains and losses, rather than abundance levels or period changes.
doi:10.1111/j.1365-2656.2008.01424.x
Prior work on geographical differences in prairie duck population dynamics.
doi:10.1002/wmon.1074
Prior work on duck distribution, wetland conditions, and productivity in the Canadian Prairie Pothole Region.

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usesSeparate pond gain and loss slopes gave no clear mean gain in spatial predictions for ten prairie duck taxa in 2000–2019
Its gain-versus-loss question and source selection guide this prediction test. We extend its annual association test with a fixed temporal model comparison.