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Species · Maryland · BBS 2026 Release · 1966–2025

Vesper Sparrow Population Trend in Maryland

All statesGrassland birds

Vesper Sparrow in Maryland has collapsed: down 97% on the route-weighted index since 1968.

-97%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 →
50Routes 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 →
59YearsYears 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 MarylandNotable 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 Maryland: down 97% on the route-weighted index since 1968.

Vesper Sparrow Population Forecast in Maryland

If the recent trend holds, Vesper Sparrow in Maryland is projected to fall about 100% by 2030 — from 0.13 in 2025 to a central estimate of 0.00 (95% range 0.00–0.89). A 5-year backtest shows a typical error of ±590.5%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2030TrendPercent 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 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.8995% 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 →
±590.5%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 Maryland is projected to fall about 100% by 2030 — from 0.13 in 2025 to a central estimate of 0.00 (95% range 0.00–0.89). A 5-year backtest shows a typical error of ±590.5%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.000.000.89
20270.000.000.89
20280.000.000.89
20290.000.000.89
20300.000.000.89

Vesper Sparrow Survey Routes in Maryland

Routes recording Vesper Sparrow in Maryland.
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 →
Fruitland819971966
Williamsport420251966
Snow Hill419711971
Harmony320171966
Vindex220051966
Eklo220011966
Randallstown219791967
Beltsville219701966
La Plata219961966
Steyer220121996
Floyd120131967
Mt Nebo119891970
Oldtown119701970
Potomac Park120171970
Smithsburg120131966
Wolfsville120181966
Emmitsburg120251966
Grove Neck119941994
Olney120081967
Bald Friar119961996
Warfieldsbrg120061966
Pleasant Val120101966
Bachman Mill120171966
Fowblesburg120111966
Upper Xrds119921966

Vesper Sparrow Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.