BirdAnalyst
Species · New Mexico · BBS 2026 Release · 1966–2025

Vesper Sparrow Population Trend in New Mexico

All statesGrassland birds

Vesper Sparrow in New Mexico has surged: up 372% on the route-weighted index since 1973.

+372%Since 1973TrendPercent 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 →
42Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Vesper Sparrow Trends in New MexicoNotable 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 increasecomputed 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 →

Vesper Sparrow has surged in New Mexico: up 372% on the route-weighted index since 1973.

Vesper Sparrow Population Forecast in New Mexico

If the recent trend holds, Vesper Sparrow in New Mexico is projected to rise about 67% by 2030 — from 2.7 in 2025 to a central estimate of 4.5 (95% range 0.68–8.3). A 5-year backtest shows a typical error of ±48.1%, with 100% of held-out values landing inside the 95% band.

+67%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 →
4.5Projected 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 →
0.68–8.395% 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 →
±48.1%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, Vesper Sparrow in New Mexico is projected to rise about 67% by 2030 — from 2.7 in 2025 to a central estimate of 4.5 (95% range 0.68–8.3). A 5-year backtest shows a typical error of ±48.1%, 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 →
20264.40.638.2
20274.50.648.3
20284.50.668.3
20294.50.678.3
20304.50.688.3

Vesper Sparrow Survey Routes in New Mexico

Routes recording Vesper Sparrow in New Mexico.
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 →
Stinking Lk.6019991992
Mt. Taylor 24920242014
Dulce4320252000
Fence Lake2820251975
Mt. Taylor2220121993
Quemado2019971995
Datil1919951993
Pecos1820171973
Angel Fire1820021992
Horse Spgs1220251975
Gallinas1120251992
Farley920251979
Maxwell720251996
Salt Lake720011999
Floyd520211970
Mountainair520171998
La Plata520131990
Salt Lake 2420222002
Claunch 2420252002
Capulin319941993
Claunch320001982
Horse Mtn320221976
Angel Fire 2320252005
Aztec319891988
Nageesi220121999

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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