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

Least Flycatcher Population Trend in Iowa

All statesAerial insectivores

Least Flycatcher in Iowa has held roughly steady: down 4% on the route-weighted index since 1970.

-4%Since 1970TrendPercent 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 →
23Routes 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 →
33YearsYears 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 IowaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Least Flycatcher in Iowa. See the full index history below.

Least Flycatcher Population Forecast in Iowa

If the recent trend holds, Least Flycatcher in Iowa is projected to stay roughly flat through 2019, near 0.04 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±20.6%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2019TrendPercent 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 →
0.04Projected 2019 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1495% 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 →
±20.6%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 Iowa is projected to stay roughly flat through 2019, near 0.04 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±20.6%, with 100% of held-out values landing inside the 95% band.19682019
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 →
20150.040.000.14
20160.040.000.14
20170.040.000.14
20180.040.000.14
20190.040.000.14

Least Flycatcher Survey Routes in Iowa

Routes recording Least Flycatcher in Iowa.
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 →
Exline219961987
Bedford219721972
Pierson219761976
Garner219751975
Mt Hamill119911974
College Spgs119691969
Desmoines119721970
Panther119731973
Washington119921975
Neola119921992
Wales119741974
Maquoketa120141969
Alice119781969
Prairieburg119761975
Hudson119791979
Scranton119761976
Clare120132007
Washta120081968
Sioux City120092009
Festina119931993
Titonka119811976
Gaza120021979
Rock Valley119721972

Least Flycatcher Population Trend in Other States

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

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