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

Cliff Swallow Population Trend in Maine

All statesAerial insectivores

Cliff Swallow in Maine has collapsed: down 95% on the route-weighted index since 1968.

-95%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 →
61Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cliff 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 →

Cliff Swallow has collapsed in Maine: down 95% on the route-weighted index since 1968.

Cliff Swallow Population Forecast in Maine

If the recent trend holds, Cliff Swallow in Maine is projected to fall about 100% by 2027 — from 0.38 in 2022 to a central estimate of 0.00 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±267.3%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2027TrendPercent 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 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–4.095% 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 →
±267.3%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, Cliff Swallow in Maine is projected to fall about 100% by 2027 — from 0.38 in 2022 to a central estimate of 0.00 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±267.3%, with 100% of held-out values landing inside the 95% band.19662027
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 →
20230.000.004.0
20240.000.004.0
20250.000.004.0
20260.000.004.0
20270.000.004.0

Cliff Swallow Survey Routes in Maine

Routes recording Cliff 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 →
Grnd Lk Strm9319931990
Baxter2119881979
Northfield2019811976
Otisfield Gr1519931966
Hermon1219931975
Forest Sta1219851967
Kittery Pt1019941967
Greenwood1019941966
Castine1020001976
Aurora1020191975
Clayton Lake1019861977
Cornville1020192019
Bowdoin Ctr820131971
Greenville820221977
Medway820141978
Ludlow719961968
Hartford520211975
Baker Lake519941994
Cape Neddick419751972
Brooks419961984
Horse Mtn419901983
Newcastle320021971
Wilson Mills320031984
East Troy320071972
Hancock320011969

Cliff Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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