BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

Willow Flycatcher Population Trend in North Dakota

All statesAerial insectivores

Willow Flycatcher in North Dakota has surged: up 179% on the route-weighted index since 1969.

+179%Since 1969TrendPercent 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 →
48Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willow Flycatcher Trends in North DakotaNotable 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 increasecomputed 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 →

Willow Flycatcher has surged in North Dakota: up 179% on the route-weighted index since 1969.

Willow Flycatcher Population Forecast in North Dakota

If the recent trend holds, Willow Flycatcher in North Dakota is projected to fall about 23% by 2030 — from 5.1 in 2025 to a central estimate of 3.9 (95% range 2.7–5.1). A 5-year backtest shows a typical error of ±26.2%, with 40% of held-out values landing inside the 95% band.

-23%Change by 2030TrendPercent 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 →
3.9Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
2.7–5.195% 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 →
±26.2%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, Willow Flycatcher in North Dakota is projected to fall about 23% by 2030 — from 5.1 in 2025 to a central estimate of 3.9 (95% range 2.7–5.1). A 5-year backtest shows a typical error of ±26.2%, with 40% of held-out values landing inside the 95% band.19672030
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 →
20263.72.54.9
20273.72.64.9
20283.82.65.0
20293.92.75.0
20303.92.75.1

Willow Flycatcher Survey Routes in North Dakota

Routes recording Willow Flycatcher in North Dakota.
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 →
Douglas Crk1920251982
Buchanan1420251967
Sheyenne Lk1320251980
Danzig 21320252019
Horsehead Lk1120251980
Forman920251969
Braddock920231988
Cooperstown820251969
Emerado720251979
Dickinson720251970
Gorham720252002
Parshall720131982
Denbigh620251968
Sydney419831978
Edgeley420251980
Dunn Center420251968
Stanley420251967
Zap420191989
Regan320251969
Tobacco320191968
Bentley320241989
Solen320252007
Lake George220231967
Danzig220131989
Carson220251997

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.