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

Bank Swallow Population Trend in Montana

All statesAerial insectivores

Bank Swallow in Montana has collapsed: down 75% on the route-weighted index since 1970.

-75%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 →
70Routes 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 Bank Swallow Trends in MontanaNotable 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 →

Bank Swallow has collapsed in Montana: down 75% on the route-weighted index since 1970.

Bank Swallow Population Forecast in Montana

If the recent trend holds, Bank Swallow in Montana is projected to fall about 43% by 2029 — from 1.7 in 2024 to a central estimate of 0.99 (95% range 0.00–6.3). A 5-year backtest shows a typical error of ±34%, with 100% of held-out values landing inside the 95% band.

-43%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 →
0.99Projected 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 →
0.00–6.395% 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 →
±34%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, Bank Swallow in Montana is projected to fall about 43% by 2029 — from 1.7 in 2024 to a central estimate of 0.99 (95% range 0.00–6.3). A 5-year backtest shows a typical error of ±34%, 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 →
20251.20.006.5
20261.20.006.4
20271.10.006.4
20281.10.006.3
20290.990.006.3

Bank Swallow Survey Routes in Montana

Routes recording Bank Swallow in Montana.
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 →
Savage9620211970
Clyde Park5120242021
Twin Bridges3919761968
Pablo Res.3420231995
Great Falls3020222022
Red Rock3019971973
Willow Creek 22620241982
Chinook2220242017
Church Hill2120242017
Wolf Point1220232016
Fort Logan920222022
Wise River919941994
Augusta820121985
Chestnut820222022
Whitlash820162011
Redstone720241968
Powderville720171972
Sunburst620071987
Victor620142014
Glasgow520191980
Circle520171973
Lima520241996
Libby Dam420011984
Oswego420221983
Forsyth420232015

Bank Swallow Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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