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Species · BCR 19 · BBS 2025 Release · 1966–2024

Least Tern In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieWetland birds

Least Tern in Central Mixed Grass Prairie has declined: down 29% on the route-weighted index since 1969.

-29%Since 1969TrendPercent 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 →
12Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Least Tern in Central Mixed Grass Prairie. See the full index history below.

Least Tern In Central Mixed Grass Prairie Population Forecast

If the recent trend holds, Least Tern in Central Mixed Grass Prairie is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±44.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.04Projected 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 →
0.00–0.0895% 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 →
±44.9%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, Least Tern in Central Mixed Grass Prairie is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±44.9%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.040.000.09
20260.040.000.09
20270.040.000.09
20280.040.000.08
20290.040.000.08

Routes In Central Mixed Grass Prairie

Routes recording Least Tern in Central Mixed Grass Prairie.
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 →
DamarKANSAS32000
KearneyNEBRASKA32024
RandlettOKLAHOMA32005
DaltonKANSAS22008
AlbertKANSAS21986
Eagle CityOKLAHOMA11989
ErickOKLAHOMA12005
TegardenOKLAHOMA11971
CashionOKLAHOMA12006
JetOKLAHOMA12012
WeinertTEXAS11990
ClarendonTEXAS11969

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