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

Vesper Sparrow Population Trend in Maine

All statesGrassland birds

Vesper Sparrow in Maine has collapsed: down 99% on the route-weighted index since 1968.

-99%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 →
31Routes 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 →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Vesper 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 →

Vesper Sparrow has collapsed in Maine: down 99% on the route-weighted index since 1968.

Vesper Sparrow Population Forecast in Maine

If the recent trend holds, Vesper Sparrow in Maine is projected to stay roughly flat through 2021, near 0.00 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±3607.5%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2021TrendPercent 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 2021 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 →
±3607.5%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, Vesper Sparrow in Maine is projected to stay roughly flat through 2021, near 0.00 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±3607.5%, with 100% of held-out values landing inside the 95% band.19662021
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 →
20170.000.004.0
20180.000.004.0
20190.000.004.0
20200.000.004.0
20210.000.004.0

Vesper Sparrow Survey Routes in Maine

Routes recording Vesper 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 →
Deblois920071966
Benton419711971
Northfield419811981
Benedicta419771977
Ashland419961980
Harmony320031969
Biddeford219771977
Bowdoin Ctr219711971
Cooper220051976
Seboomook Lk220071999
Cape Neddick119781978
Northfield 2119961996
Turner119901974
South Arm119951990
Otisfield Gr119791966
Manchester119811973
Topsfield119791979
Hermon119821966
Eastbrook120161972
Hancock120121969
Castine119831983
Aurora120091988
Carrabassett119981998
Cambridge119731968
Hudson119821973

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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