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

Horned Lark Population Trend in Maine

All statesGrassland birds

Horned Lark in Maine has collapsed: down 83% on the route-weighted index since 1979.

-83%Since 1979TrendPercent 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 →
8Routes 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 →
22YearsYears 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 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 →

Horned Lark has collapsed in Maine: down 83% on the route-weighted index since 1979.

Horned Lark Population Forecast in Maine

If the recent trend holds, Horned Lark in Maine is projected to rise about 40% by 2010 — from 0.07 in 2005 to a central estimate of 0.10 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±375.4%, with 100% of held-out values landing inside the 95% band.

+40%Change by 2010TrendPercent 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 →
0.10Projected 2010 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3995% 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 →
±375.4%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 Maine is projected to rise about 40% by 2010 — from 0.07 in 2005 to a central estimate of 0.10 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±375.4%, with 100% of held-out values landing inside the 95% band.19682010
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 →
20060.120.000.42
20070.120.000.41
20080.110.000.40
20090.100.000.40
20100.100.000.39

Horned Lark Survey Routes in Maine

Routes recording Horned Lark 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 →
Harmony619901990
Brooks319791979
Medway219761976
Washburn220051979
Ludlow119861968
Boundary120041993
Ft Fairfield120041993
St David120051984

Horned Lark Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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