BirdAnalyst
Species · Pennsylvania · BBS 2026 Release · 1966–2025

Horned Lark Population Trend in Pennsylvania

All statesGrassland birds

Horned Lark in Pennsylvania has fallen sharply: down 58% on the route-weighted index since 1968.

-58%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 →
100Routes 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 Horned Lark 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 →

Horned Lark has fallen sharply in Pennsylvania: down 58% on the route-weighted index since 1968.

Horned Lark Population Forecast in Pennsylvania

If the recent trend holds, Horned Lark in Pennsylvania is projected to fall about 39% by 2030 — from 0.71 in 2025 to a central estimate of 0.44 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±27.7%, with 100% of held-out values landing inside the 95% band.

-39%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 →
0.44Projected 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 →
0.00–1.295% 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 →
±27.7%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, Horned Lark in Pennsylvania is projected to fall about 39% by 2030 — from 0.71 in 2025 to a central estimate of 0.44 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±27.7%, 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 →
20260.450.001.2
20270.450.001.2
20280.440.001.2
20290.440.001.2
20300.440.001.2

Horned Lark Survey Routes in Pennsylvania

Routes recording Horned Lark 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 →
Leola1020251998
St College920251970
Williamsburg820251992
Brunnerville720091969
Brunnerville 2620252010
Akeley519791966
Martinsburg420251970
Geeseytown420251988
Sporting Hil419771977
Shrewsbury420231991
Portersville319761976
Beaver319831983
Bald Eagle320251969
Ephrata319791969
Middletown320191974
Carsonville320231966
New Ringgold320251966
Normalville319671966
Doylesburg320192009
Akron319971989
Schaefferstown 2320252002
Drehersville 2320152015
Stoneybreak320251992
Chatham320251997
Harmonsburg220041966

Horned Lark Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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