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

Bank Swallow Population Trend in Massachusetts

All statesAerial insectivores

Bank Swallow in Massachusetts has fallen sharply: down 53% on the route-weighted index since 1968.

-53%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 →
28Routes 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 MassachusettsNotable 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 fallen sharply in Massachusetts: down 53% on the route-weighted index since 1968.

Bank Swallow Population Forecast in Massachusetts

If the recent trend holds, Bank Swallow in Massachusetts is projected to fall about 100% by 2029 — from 0.20 in 2024 to a central estimate of 0.00 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±134.2%, 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 →
0.00–2.295% 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 →
±134.2%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 Massachusetts is projected to fall about 100% by 2029 — from 0.20 in 2024 to a central estimate of 0.00 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±134.2%, 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 →
20250.000.002.2
20260.000.002.2
20270.000.002.2
20280.000.002.2
20290.000.002.2

Bank Swallow Survey Routes in Massachusetts

Routes recording Bank Swallow in Massachusetts.
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 →
Cheshire3719931970
Newburyport1519721967
Littleton1020041969
E Pepperell519701970
Ware River519991993
Gay Head520231996
Mansfield420071989
E Dennis320021977
Prattville319711968
N Orange319921971
Holden320051978
Chilmark219751971
Marion220241999
Wellfleet219661966
N Oxford220131969
Princeton219741969
Cummington220141969
Cape Cod Ns219991990
Cummington 2220212016
Brockton120101967
Maynard120191969
Belchertown120241967
Warren120091968
S Barre120021969
Chesterfield120161967

Bank Swallow Population Trend in Other States

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

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