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

Horned Lark Population Trend in Arizona

All statesGrassland birds

Horned Lark in Arizona has fallen sharply: down 72% on the route-weighted index since 1970.

-72%Since 1970TrendPercent 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 →
72Routes 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 →
57YearsYears 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 ArizonaNotable 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 Arizona: down 72% on the route-weighted index since 1970.

Horned Lark Population Forecast in Arizona

If the recent trend holds, Horned Lark in Arizona is projected to fall about 85% by 2030 — from 10 in 2025 to a central estimate of 1.5 (95% range 0.00–15). A 5-year backtest shows a typical error of ±72.4%, with 100% of held-out values landing inside the 95% band.

-85%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 →
1.5Projected 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 →
0.00–1595% 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 →
±72.4%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 Arizona is projected to fall about 85% by 2030 — from 10 in 2025 to a central estimate of 1.5 (95% range 0.00–15). A 5-year backtest shows a typical error of ±72.4%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20263.60.0017
20273.10.0017
20282.60.0016
20292.00.0016
20301.50.0015

Horned Lark Survey Routes in Arizona

Routes recording Horned Lark in Arizona.
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 →
Mt Trumbull16719931974
Many Farms15820061993
Rose Wells8419781968
Yampai7519771969
Oraibi6420221991
Coolidge5819851974
Seligman5720251991
Castle Butte5320251992
Clay Spring5020251988
The Gap4319761968
Rucker4220091993
Peach Spring3920251992
Skull Valley 23820252025
Navajo Trail3720251994
Willow Beach 23220252004
Round Rock3119891968
Toroweap2520251994
Zeniff1919841968
Forest Lakes1920251992
Palo Verde1820131992
Hunt1720181968
Laguna1720231968
Hope 21620182014
Black Mesa1519951988
Casa Grande1420231989

Horned Lark Population Trend in Other States

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

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