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

Barn Swallow Population Trend in Idaho

All statesAerial insectivores

Barn Swallow in Idaho has fallen sharply: down 71% on the route-weighted index since 1970.

-71%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 →
56Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Barn Swallow 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 declinecomputed 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 →

Barn Swallow has fallen sharply in Idaho: down 71% on the route-weighted index since 1970.

Barn Swallow Population Forecast in Idaho

If the recent trend holds, Barn Swallow in Idaho is projected to fall about 97% by 2029 — from 3.0 in 2024 to a central estimate of 0.09 (95% range 0.00–9.8). A 5-year backtest shows a typical error of ±70.3%, with 100% of held-out values landing inside the 95% band.

-97%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 →
0.00–9.895% 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 →
±70.3%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, Barn Swallow in Idaho is projected to fall about 97% by 2029 — from 3.0 in 2024 to a central estimate of 0.09 (95% range 0.00–9.8). A 5-year backtest shows a typical error of ±70.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20251.40.0011
20261.10.0011
20270.770.0011
20280.430.0010
20290.090.009.8

Barn Swallow Survey Routes in Idaho

Routes recording Barn Swallow 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 →
Glenns Ferry6719861968
Mud Lake3920231988
Blacks Creek3820171968
Pocatello3520191979
Cedar Hill3220241989
Cascade2919841968
Springfield2220181969
Ririe1920231971
Gifford1720171971
Henry1719831973
Hot Spring1020141988
Dubois820241969
Picabo820211988
Naples720241972
Craters720181979
Acequia720121979
Coolin720241986
Preston720231988
Sawtooth City 2520242015
Joel520241989
Crane Creek520191988
Almo520231988
Mora520242018
Avery419891989
Daniels Res420191988

Barn Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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