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

Barn Swallow Population Trend in Maine

All statesAerial insectivores

Barn Swallow in Maine has collapsed: down 90% on the route-weighted index since 1968.

-90%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 →
73Routes 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 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 →

Barn Swallow has collapsed in Maine: down 90% on the route-weighted index since 1968.

Barn Swallow Population Forecast in Maine

If the recent trend holds, Barn Swallow in Maine is projected to fall about 100% by 2029 — from 4.3 in 2024 to a central estimate of 0.00 (95% range 0.00–11). A 5-year backtest shows a typical error of ±315.8%, with 20% 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 →
0.00–1195% 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 →
±315.8%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, Barn Swallow in Maine is projected to fall about 100% by 2029 — from 4.3 in 2024 to a central estimate of 0.00 (95% range 0.00–11). A 5-year backtest shows a typical error of ±315.8%, with 20% 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 →
20250.000.0011
20260.000.0011
20270.000.0011
20280.000.0011
20290.000.0011

Barn Swallow Survey Routes in Maine

Routes recording Barn 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 →
Forest Sta4820001966
Northfield3119811976
Benton2719801971
Charleston1520181975
Brownfield1520092009
Jefferson1520101991
Topsfield1419961978
Stacyville1320242021
Cornville1220242012
Grnd Lk Strm1120001966
Warren1019901973
Aurora1020211975
Benedicta1020221976
Hartford920241975
Brooks920181977
Waite919771977
Bethel820191972
Bowdoin Ctr820211971
Wytopitlock819981976
Reeds720241983
Otisfield Gr720151966
Washburn720051979
Brownfield 2720132010
Westbrook620241977
Carrabassett620241983

Barn Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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