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

Field Sparrow Population Trend in Maine

All statesGeneralists

Field Sparrow in Maine has collapsed: down 87% on the route-weighted index since 1968.

-87%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 →
43Routes 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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Field Sparrow 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 →

Field Sparrow has collapsed in Maine: down 87% on the route-weighted index since 1968.

Field Sparrow Population Forecast in Maine

If the recent trend holds, Field Sparrow in Maine is projected to fall about 100% by 2027 — from 0.10 in 2022 to a central estimate of 0.00 (95% range 0.00–0.54). A 5-year backtest shows a typical error of ±400.2%, 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 →
0.00–0.5495% 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 →
±400.2%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, Field Sparrow in Maine is projected to fall about 100% by 2027 — from 0.10 in 2022 to a central estimate of 0.00 (95% range 0.00–0.54). A 5-year backtest shows a typical error of ±400.2%, 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 →
20230.000.000.54
20240.000.000.54
20250.000.000.54
20260.000.000.54
20270.000.000.54

Field Sparrow Survey Routes in Maine

Routes recording Field Sparrow 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 →
Benton819771971
Greenville519721972
Westbrook419951977
Turner419961972
Freedom220081973
Charleston219771977
Hudson219801973
Cape Neddick119881972
Biddeford120181973
Kittery Pt119681968
Newcastle119761972
Northfield 2120222022
Bethel119791978
Greenwood120191974
Reeds119961990
South Arm119991995
Otisfield Gr119861977
Hartford120181976
Bowdoin Ctr120211979
Manchester119831971
East Troy119821973
Warren119891973
Harmony120211967
Brooks119791979
Hermon119881966

Field Sparrow Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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