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

Least Flycatcher Population Trend in Idaho

All statesAerial insectivores

Least Flycatcher in Idaho has surged: up 170% on the route-weighted index since 1991.

+170%Since 1991TrendPercent 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 →
14Routes 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 →
28YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Least Flycatcher 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 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 →

Least Flycatcher has surged in Idaho: up 170% on the route-weighted index since 1991.

Least Flycatcher Population Forecast in Idaho

If the recent trend holds, Least Flycatcher in Idaho is projected to fall about 25% by 2029 — from 0.24 in 2024 to a central estimate of 0.18 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±69.6%, with 60% of held-out values landing inside the 95% band.

-25%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 →
0.18Projected 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 →
0.00–0.4295% 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 →
±69.6%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, Least Flycatcher in Idaho is projected to fall about 25% by 2029 — from 0.24 in 2024 to a central estimate of 0.18 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±69.6%, with 60% of held-out values landing inside the 95% band.19792029
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 →
20250.170.000.41
20260.170.000.41
20270.170.000.42
20280.180.000.42
20290.180.000.42

Least Flycatcher Survey Routes in Idaho

Routes recording Least Flycatcher 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 →
Yellow Pine719931992
Naples620241979
Magic Mtn619901990
Lolo Pass220191992
Baker220102010
Burgdorf219921992
Featherville219961991
Mivoden120232023
Gifford120172017
Joel120232017
Challis120092001
Leadore120122012
Cobalt120072007
Coolin120232003

Least Flycatcher Population Trend in Other States

alaskaarkansascaliforniacoloradoconnecticutgeorgiaillinoisindianaiowakentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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