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

Common Loon Population Trend in Maine

All statesWetland birds

Common Loon in Maine has surged: up 111% on the route-weighted index since 1968.

+111%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 →
65Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Loon 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 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 →

Common Loon has surged in Maine: up 111% on the route-weighted index since 1968.

Common Loon Population Forecast in Maine

If the recent trend holds, Common Loon in Maine is projected to fall about 23% by 2029 — from 1.4 in 2024 to a central estimate of 1.1 (95% range 0.61–1.6). A 5-year backtest shows a typical error of ±19.3%, with 100% of held-out values landing inside the 95% band.

-23%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 →
1.1Projected 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 →
0.61–1.695% 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 →
±19.3%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, Common Loon in Maine is projected to fall about 23% by 2029 — from 1.4 in 2024 to a central estimate of 1.1 (95% range 0.61–1.6). A 5-year backtest shows a typical error of ±19.3%, 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 →
20251.10.571.6
20261.10.581.6
20271.10.591.6
20281.10.601.6
20291.10.611.6

Common Loon Survey Routes in Maine

Routes recording Common Loon 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 →
Kittery Pt720241986
Lake Moxie720222006
Seboomook Lk620141972
St David620041985
Newcastle420081971
Eastbrook420241971
Carrying Pl420241979
Wilson Mills320241984
Greenwood320241972
Northfield319811976
Weeks Brook320161996
Reeds220142014
Harmony220241970
Brooks220171977
Castine220051976
Cooper220191975
Greenville220221976
Grnd Lk Strm220001966
Clayton Lake220011984
Ludlow219961986
Horse Mtn220111983
Cornville220242012
Telos220061995
Priestly Br.219981995
Baker Lake220091995

Common Loon Population Trend in Other States

alaskaidahomassachusettsmichiganminnesotamontananew-hampshirenew-yorknorth-dakotaoregonvermontwashingtonwisconsinwyoming

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