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

Barn Swallow Population Trend in Pennsylvania

All statesAerial insectivores

Barn Swallow in Pennsylvania has edged down: down 21% on the route-weighted index since 1968.

-21%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 →
134Routes 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 PennsylvaniaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Barn Swallow in Pennsylvania. See the full index history below.

Barn Swallow Population Forecast in Pennsylvania

If the recent trend holds, Barn Swallow in Pennsylvania is projected to stay roughly flat through 2029, near 17 (95% range 11–23). A 5-year backtest shows a typical error of ±8.6%, with 100% of held-out values landing inside the 95% band.

+1%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 →
17Projected 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 →
11–2395% 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 →
±8.6%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 Pennsylvania is projected to stay roughly flat through 2029, near 17 (95% range 11–23). A 5-year backtest shows a typical error of ±8.6%, 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 →
2025181224
2026181224
2027181224
2028171123
2029171123

Barn Swallow Survey Routes in Pennsylvania

Routes recording Barn Swallow in Pennsylvania.
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 →
Ralston11319781966
Leola7520241998
Drehersville 26320242000
Normalville6219741966
Drehersville6019991966
Mount Joy5520241978
Ravensburg5419801966
Sugar Grove5420241980
Akeley4919791966
Quakertown4919891970
Schaefferstown 24920242002
Big Flat4419811966
Portersville4319881973
Scheafferstn4320011966
Labott4319831966
Waterstreet4220241968
Doubling Gap4219771966
Akron4219971989
Teepleville3920241966
Aspers3919891968
Brick Tavern3720241990
Lovelton3720231999
Chatham3620241997
Naginey3520241970
Williamsburg3420241988

Barn Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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