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

Vesper Sparrow Population Trend in Pennsylvania

All statesGrassland birds

Vesper Sparrow in Pennsylvania has collapsed: down 96% on the route-weighted index since 1968.

-96%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 →
104Routes 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 Vesper Sparrow Trends in PennsylvaniaNotable 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 Pennsylvania: down 96% on the route-weighted index since 1968.

Vesper Sparrow Population Forecast in Pennsylvania

If the recent trend holds, Vesper Sparrow in Pennsylvania is projected to fall about 100% by 2029 — from 0.09 in 2024 to a central estimate of 0.00 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±337.5%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.7195% 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 →
±337.5%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 Pennsylvania is projected to fall about 100% by 2029 — from 0.09 in 2024 to a central estimate of 0.00 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±337.5%, 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 →
20250.000.000.71
20260.000.000.71
20270.000.000.71
20280.000.000.71
20290.000.000.71

Vesper Sparrow Survey Routes in Pennsylvania

Routes recording Vesper Sparrow in Pennsylvania.
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 →
Needmore619911966
Ravensburg519661966
Brunnerville520091969
Pottersdale419941969
Normalville419701966
Big Flat419811967
Akeley319701967
Mifflintown320021966
Carsonville320161966
Quakertown319721971
Jeannette320221979
Jacobus319941986
Roulette219881988
Rosecrans220191969
Ralston219661966
Waller220231971
Honesdale220111974
Starlight219971970
Plesant Grov219921989
Parkwood220041967
Kittanning220231987
Virginia220011969
Geeseytown220241994
St College220241969
Peters Mt219761974

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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