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

Horned Lark Population Trend in Arizona

All statesGrassland birds

Horned Lark in Arizona has fallen sharply: down 73% on the route-weighted index since 1970.

-73%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 →
70Routes 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 →
56YearsYears 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 73% 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 87% by 2029 — from 12 in 2024 to a central estimate of 1.5 (95% range 0.00–15). A 5-year backtest shows a typical error of ±66.4%, with 100% of held-out values landing inside the 95% band.

-87%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 →
1.5Projected 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 →
0.00–1595% 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 →
±66.4%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 87% by 2029 — from 12 in 2024 to a central estimate of 1.5 (95% range 0.00–15). A 5-year backtest shows a typical error of ±66.4%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20253.60.0017
20263.10.0017
20272.60.0016
20282.10.0016
20291.50.0015

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
Navajo Trail7620241994
Yampai7519771969
Seligman7420241991
Oraibi6420221991
Clay Spring6320241988
Coolidge5819851974
Castle Butte5120071992
Peach Spring4420241992
The Gap4319761968
Rucker4220091993
Forest Lakes3620241992
Round Rock3119891968
Zeniff1919841968
Antares1920241994
Palo Verde1820131992
Hunt1720181968
Laguna1720231968
Hope 21620182014
Black Mesa1519951988
Patagonia1520241968
Palo Verde 21520242014
Toroweap1520241994

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 2026-05-22.