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

Bank Swallow Population Trend in Connecticut

All statesAerial insectivores

Bank Swallow in Connecticut has surged: up 77% on the route-weighted index since 1968.

+77%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 →
17Routes 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 →
54YearsYears 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 ConnecticutNotable 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 →

Bank Swallow has surged in Connecticut: up 77% on the route-weighted index since 1968.

Bank Swallow Population Forecast in Connecticut

If the recent trend holds, Bank Swallow in Connecticut is projected to rise about 383% by 2028 — from 0.27 in 2023 to a central estimate of 1.3 (95% range 0.00–3.7). A 5-year backtest shows a typical error of ±360.9%, with 100% of held-out values landing inside the 95% band.

+383%Change by 2028TrendPercent 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 →
1.3Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–3.795% 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 →
±360.9%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 Connecticut is projected to rise about 383% by 2028 — from 0.27 in 2023 to a central estimate of 1.3 (95% range 0.00–3.7). A 5-year backtest shows a typical error of ±360.9%, with 100% of held-out values landing inside the 95% band.19662028
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 →
20241.30.003.7
20251.30.003.7
20261.30.003.7
20271.30.003.7
20281.30.003.7

Bank Swallow Survey Routes in Connecticut

Routes recording Bank Swallow in Connecticut.
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 →
Granby1220141989
Mystic720041973
Woodstock519761976
No Woodbury520111968
Buckingham420221972
Sherman320031991
Mid Haddam320231975
Westbrook219991969
New Hartford219981994
Danbury220101976
Long Hill220191973
Southington219801980
New Hartford219871972
E Hartland119921966
Uncasville120181984
Willimantic120071981
Warren120111972

Bank Swallow Population Trend in Other States

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

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