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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Horned Lark Population Trend in Pennsylvania

All statesGrassland birds

Horned Lark in Pennsylvania has fallen sharply: down 62% on the route-weighted index since 1968.

-62%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 →
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 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 62% 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 22% by 2029 — from 0.54 in 2024 to a central estimate of 0.42 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±31.6%, with 100% of held-out values landing inside the 95% band.

-22%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 →
0.42Projected 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 →
0.00–1.295% 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 →
±31.6%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 22% by 2029 — from 0.54 in 2024 to a central estimate of 0.42 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±31.6%, 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 →
20250.430.001.2
20260.430.001.2
20270.430.001.2
20280.420.001.2
20290.420.001.2

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 →
Leola1720241998
Brunnerville720091969
Martinsburg620241970
Geeseytown620231988
Akeley519791966
Teepleville520181969
Williamsburg520241992
Stoneybreak520241992
Sporting Hil419771977
Harrisville420231997
Shrewsbury420231991
Chatham420241997
Portersville319761976
Beaver319831983
Ephrata319791969
Middletown320191974
Carsonville320231966
Normalville319671966
Doylesburg320192009
Akron319971989
Drehersville 2320152015
Harmonsburg220041966
Ferris Crnrs220081966
Whig Hill219741974
N Pine Grove220111969

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 2026-05-22.