BirdAnalyst
Species · Idaho · BBS 2025 Release · 1966–2024

Willet Population Trend in Idaho

All statesShorebirds

Willet in Idaho has fallen sharply: down 56% on the route-weighted index since 1972.

-56%Since 1972TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
20Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willet Trends in IdahoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Willet has fallen sharply in Idaho: down 55% on the route-weighted index since 1972.

Willet Population Forecast in Idaho

If the recent trend holds, Willet in Idaho is projected to fall about 37% by 2029 — from 0.44 in 2024 to a central estimate of 0.28 (95% range 0.00–0.91). A 5-year backtest shows a typical error of ±60.1%, with 100% of held-out values landing inside the 95% band.

-37%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.28Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.9195% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±60.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Willet in Idaho is projected to fall about 37% by 2029 — from 0.44 in 2024 to a central estimate of 0.28 (95% range 0.00–0.91). A 5-year backtest shows a typical error of ±60.1%, with 100% of held-out values landing inside the 95% band.19702029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.300.000.93
20260.290.000.93
20270.290.000.92
20280.280.000.92
20290.280.000.91

Willet Survey Routes in Idaho

Routes recording Willet in Idaho.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Henry1019811974
Dubois920241971
Mud Lake420191988
Bates320191988
Blackft Res220181984
Kyle Canyon219991999
Tractor Flat220231989
Craters219931988
Springfield220071970
Twin Buttes120181999
Circular Bu119961996
Leadore120241987
Ririe120091986
Acequia119881979
Pocatello119791979
Iron Springs120241991
Picabo120171989
Carey119921992
Preston120091988
Pasadena Val120111990

Willet Population Trend in Other States

alabamacaliforniacoloradoconnecticutdelawarefloridalouisianamainemarylandmassachusettsminnesotamontananebraskanevadanew-jerseynew-yorknorth-carolinanorth-dakotaoregonsouth-carolinasouth-dakotatexasutahvirginiawyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.