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

Fox Sparrow Population Trend in Maine

All statesGeneralists

Fox Sparrow in Maine has edged up: up 20% on the route-weighted index since 1995.

+20%Since 1995TrendPercent 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 →
11Routes 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 →
23YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Fox 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 →

No notable trend signals for Fox Sparrow in Maine. See the full index history below.

Fox Sparrow Population Forecast in Maine

If the recent trend holds, Fox Sparrow in Maine is projected to fall about 28% by 2026 — from 0.12 in 2021 to a central estimate of 0.09 (95% range 0.00–0.43). A 5-year backtest shows a typical error of ±70%, with 100% of held-out values landing inside the 95% band.

-28%Change by 2026TrendPercent 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 →
0.09Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4395% 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 →
±70%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, Fox Sparrow in Maine is projected to fall about 28% by 2026 — from 0.12 in 2021 to a central estimate of 0.09 (95% range 0.00–0.43). A 5-year backtest shows a typical error of ±70%, with 100% of held-out values landing inside the 95% band.19932026
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 →
20220.110.000.45
20230.100.000.45
20240.100.000.44
20250.090.000.44
20260.090.000.43

Fox Sparrow Survey Routes in Maine

Routes recording Fox 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 →
Heron Lake820031997
Priestly Br.720011994
Clayton Lake 2320132013
Wilson Mills220212017
Clayton Lake220012001
Seboomook Lk120102007
Winn119961996
Nesowadnehun120212016
Big Twenty120061993
Weeks Brook120081995
Yankeetuladi120091994

Fox Sparrow Population Trend in Other States

alaskacaliforniacoloradoidahomontananevadaoregonutahwashingtonwyoming

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