BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Willow Flycatcher Population Trend in North Dakota

All statesAerial insectivores

Willow Flycatcher in North Dakota has surged: up 171% on the route-weighted index since 1969.

+171%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 →
57YearsYears 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 171% 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 stay roughly flat through 2029, near 3.7 (95% range 2.6–4.8). A 5-year backtest shows a typical error of ±24.8%, with 60% of held-out values landing inside the 95% band.

+6%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 →
3.7Projected 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 →
2.6–4.895% 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 →
±24.8%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 stay roughly flat through 2029, near 3.7 (95% range 2.6–4.8). A 5-year backtest shows a typical error of ±24.8%, with 60% of held-out values landing inside the 95% band.19672029
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 →
20253.52.44.6
20263.62.54.7
20273.62.54.7
20283.72.64.8
20293.72.64.8

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 Crk1720241982
Buchanan1220241967
Sheyenne Lk1220241980
Regan1020221969
Horsehead Lk920241980
Danzig 2820242019
Parshall720131982
Dickinson620241970
Emerado520241979
Glen Ullin520221988
Braddock520221988
Sydney419831978
Lake George420221967
Cooperstown420241969
Zap420191989
Edgeley320241980
Tobacco320191968
Denbigh320241968
Bentley320241989
Forman220241969
Danzig220131989
Carson220241997
Nash220161980
Niles220231989
Stanley220241967

Willow Flycatcher Population Trend in Other States

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

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