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

Barred Owl Population Trend in Iowa

All statesGeneralists

Barred Owl in Iowa has risen sharply: up 65% on the route-weighted index since 1973.

+65%Since 1973TrendPercent 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 →
19Routes 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 →
39YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Barred Owl 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 →

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 →

Barred Owl has risen sharply in Iowa: up 65% on the route-weighted index since 1973.

Barred Owl Population Forecast in Iowa

If the recent trend holds, Barred Owl in Iowa is projected to fall about 49% by 2029 — from 0.18 in 2024 to a central estimate of 0.09 (95% range 0.00–0.20). A 5-year backtest shows a typical error of ±40.3%, with 100% of held-out values landing inside the 95% band.

-49%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 →
0.09Projected 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 →
0.00–0.2095% 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 →
±40.3%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, Barred Owl in Iowa is projected to fall about 49% by 2029 — from 0.18 in 2024 to a central estimate of 0.09 (95% range 0.00–0.20). A 5-year backtest shows a typical error of ±40.3%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.090.000.20
20260.090.000.20
20270.090.000.20
20280.090.000.20
20290.090.000.20

Barred Owl Survey Routes in Iowa

Routes recording Barred Owl 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 →
Washta319781978
Exline220241988
College Spgs220041979
Cedar Valley219921986
Neola219791979
Maquoketa220152015
Mt Hamill120241996
Melrose120241989
Bedford119751969
Bryant120132013
Red Rock120151998
Washington120171976
Alice119941976
Prairieburg119981974
Hudson120071973
Dinsdale119841978
Zearing119931993
Festina119911991
College Spgs 2120142010

Barred Owl Population Trend in Other States

alabamaalaskaarkansascaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawashingtonwest-virginiawisconsin

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