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

Common Grackle Population Trend in Maine

All statesGeneralists

Common Grackle in Maine has fallen sharply: down 67% on the route-weighted index since 1968.

-67%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 →
76Routes 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 Common Grackle 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 →

Common Grackle has fallen sharply in Maine: down 67% on the route-weighted index since 1968.

Common Grackle Population Forecast in Maine

If the recent trend holds, Common Grackle in Maine is projected to fall about 71% by 2029 — from 8.9 in 2024 to a central estimate of 2.5 (95% range 0.00–8.7). A 5-year backtest shows a typical error of ±47.3%, with 100% of held-out values landing inside the 95% band.

-71%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 →
2.5Projected 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 →
0.00–8.795% 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 →
±47.3%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 Grackle in Maine is projected to fall about 71% by 2029 — from 8.9 in 2024 to a central estimate of 2.5 (95% range 0.00–8.7). A 5-year backtest shows a typical error of ±47.3%, 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 →
20253.80.0010.0
20263.50.009.7
20273.20.009.3
20282.90.009.0
20292.50.008.7

Common Grackle Survey Routes in Maine

Routes recording Common Grackle 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 →
Washburn4520051979
Kittery Pt3620241966
St David3320051982
Warren3219901973
Boundary2820161993
Westbrook2620241977
Rome2120241996
Ft Fairfield2020051993
Grnd Lk Strm1720001966
Otisfield Gr1620151966
Hartford1520231975
Benton1419801971
Charleston1220191975
Cornville1220242012
Turner1120101972
Greenwood1120241966
Searsport1120242002
Waite1019771977
Church Hill1020171991
Biddeford920191973
Eastbrook920241971
Castine920061976
Manchester819951971
Greenville820221972
Medway820181976

Common Grackle Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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