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Species · Nebraska · BBS 2025 Release · 1966–2024

Cassin's Sparrow Population Trend in Nebraska

All statesGrassland birds

Cassin's Sparrow in Nebraska has fallen sharply: down 65% on the route-weighted index since 1976.

-65%Since 1976TrendPercent 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 →
11Routes 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 →
29YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cassin's Sparrow Trends in NebraskaNotable 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 →

Cassin's Sparrow has fallen sharply in Nebraska: down 65% on the route-weighted index since 1976.

Cassin's Sparrow Population Forecast in Nebraska

If the recent trend holds, Cassin's Sparrow in Nebraska is projected to fall about 14% by 2029 — from 0.15 in 2024 to a central estimate of 0.13 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±47.3%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.13Projected 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 →
0.00–0.4695% 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 →
±47.3%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, Cassin's Sparrow in Nebraska is projected to fall about 14% by 2029 — from 0.15 in 2024 to a central estimate of 0.13 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±47.3%, with 100% of held-out values landing inside the 95% band.19742029
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 →
20250.140.000.47
20260.130.000.47
20270.130.000.47
20280.130.000.46
20290.130.000.46

Cassin's Sparrow Survey Routes in Nebraska

Routes recording Cassin's Sparrow in Nebraska.
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 →
Murray Lake520241990
Benkelman420221998
Agate 2220222011
Arthur220001998
Crescent Lk220162003
Dalton220241974
Agate219741974
Stratton120181975
Crawford120112011
Paxton120122011
Culbertson120182018

Cassin's Sparrow Population Trend in Other States

arizonaarkansascaliforniacoloradokansasnew-mexicooklahomatexaswyoming

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