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

Barn Swallow Population Trend in Vermont

All statesAerial insectivores

Barn Swallow in Vermont has collapsed: down 79% on the route-weighted index since 1968.

-79%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 →
26Routes 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 →
58YearsYears 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 VermontNotable 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 collapsed in Vermont: down 79% on the route-weighted index since 1968.

Barn Swallow Population Forecast in Vermont

If the recent trend holds, Barn Swallow in Vermont is projected to fall about 100% by 2029 — from 6.6 in 2024 to a central estimate of 0.00 (95% range 0.00–8.4). A 5-year backtest shows a typical error of ±125.6%, with 80% 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 →
0.00–8.495% 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 →
±125.6%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 Vermont is projected to fall about 100% by 2029 — from 6.6 in 2024 to a central estimate of 0.00 (95% range 0.00–8.4). A 5-year backtest shows a typical error of ±125.6%, with 80% 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 →
20250.000.008.4
20260.000.008.4
20270.000.008.4
20280.000.008.4
20290.000.008.4

Barn Swallow Survey Routes in Vermont

Routes recording Barn Swallow in Vermont.
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 →
Waterville4219801967
Hinesburg3319941966
Colchester2320241986
St Johnsbury1820241970
Hardwick1220241966
Shaftsbury1020241966
Bristol920181995
Landgrove820241966
Marlboro720241966
W Rutland720241966
East Haven720241966
Fletcher720241968
Gaysville620211966
Post Mills620241966
Stowe420241988
Northfld Fls320211980
Grand Isle320241967
North Pownal220241966
S Reading220241966
S Wallingfrd220211966
Newbury220041986
Stratton120241966
Middlesex120241968
East Calais120231966
Greensboro120211967

Barn Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvirginiawashingtonwest-virginiawisconsinwyoming

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