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

Bank Swallow Population Trend in Maine

All statesAerial insectivores

Bank Swallow in Maine has collapsed: down 92% on the route-weighted index since 1968.

-92%Since 1968TrendPercent 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 →
52Routes 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 →
57YearsYears 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 MaineNotable 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 Maine: down 92% on the route-weighted index since 1968.

Bank Swallow Population Forecast in Maine

If the recent trend holds, Bank Swallow in Maine is projected to fall about 100% by 2029 — from 0.63 in 2024 to a central estimate of 0.00 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±456.8%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–4.695% 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 →
±456.8%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 Maine is projected to fall about 100% by 2029 — from 0.63 in 2024 to a central estimate of 0.00 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±456.8%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.000.004.6
20260.000.004.6
20270.000.004.6
20280.000.004.6
20290.000.004.6

Bank Swallow Survey Routes in Maine

Routes recording Bank Swallow in Maine.
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 →
East Troy3919961972
Topsfield3919781978
Eastbrook3119961973
Warren2119901973
Benton1619791971
Hartford1220241975
Forest Sta1219851966
Northfield919811976
Washburn919791979
Bethel820191977
Cambridge820081967
Westbrook719931977
Wytopitlock719971978
Freedom619961974
St David619961982
Otisfield Gr520101971
Deblois519911966
Church Hill520171991
Cape Neddick419721972
Newcastle419891971
Manchester419901971
Benedicta419801976
Cornville420122012
Moose River319841984
Seboomook Lk320001973

Bank Swallow Population Trend in Other States

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

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