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

Lark Sparrow Population Trend in Arizona

All statesGrassland birds

Lark Sparrow in Arizona has fallen sharply: down 68% on the route-weighted index since 1970.

-68%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 →
65Routes 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 Lark Sparrow 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 →

Lark Sparrow has fallen sharply in Arizona: down 68% on the route-weighted index since 1970.

Lark Sparrow Population Forecast in Arizona

If the recent trend holds, Lark Sparrow in Arizona is projected to fall about 20% by 2030 — from 2.2 in 2025 to a central estimate of 1.8 (95% range 0.00–4.8). A 5-year backtest shows a typical error of ±21.2%, with 100% of held-out values landing inside the 95% band.

-20%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 →
1.8Projected 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 →
0.00–4.895% 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 →
±21.2%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, Lark Sparrow in Arizona is projected to fall about 20% by 2030 — from 2.2 in 2025 to a central estimate of 1.8 (95% range 0.00–4.8). A 5-year backtest shows a typical error of ±21.2%, 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 →
20261.90.005.0
20271.90.004.9
20281.90.004.9
20291.80.004.8
20301.80.004.8

Lark Sparrow Survey Routes in Arizona

Routes recording Lark Sparrow 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 Trumbull4019931974
Skull Valley2220241996
Skull Valley 21720252025
Castle Butte1720251992
Toroweap1220251994
Clay Spring1020251988
Forest Lakes920251993
Yampai819771969
Florence819751974
Tsaile820232017
Black Mesa719951989
Oraibi720221992
Zeniff719841968
Dragoon720091993
Round Rock619761968
Mormon Lake619751969
Palo Verde620131999
Navajo Trail620221996
Seligman620251991
Dateland520161999
Sunizona519971968
Greasewood520031995
House Rock420221968
Flagstaff420251999
San Simon420012001

Lark Sparrow Population Trend in Other States

alabamaarkansascaliforniacoloradoidahoillinoisindianaiowakansaskentuckylouisianaminnesotamississippimissourimontananebraskanevadanew-mexiconorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

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