BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Least Tern In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieWetland birds

Least Tern in Eastern Tallgrass Prairie has held roughly steady: up 8% on the route-weighted index since 1997.

+8%Since 1997TrendPercent 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 →
7Routes 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 →
20YearsYears 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 Eastern Tallgrass Prairie. See the full index history below.

Least Tern In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Least Tern in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±41.7%, 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 →
0.02Projected 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 →
0.00–0.0395% 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 →
±41.7%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 Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±41.7%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.020.000.03
20260.020.000.03
20270.020.000.03
20280.020.000.03
20290.020.000.03

Routes In Eastern Tallgrass Prairie

Routes recording Least Tern in Eastern Tallgrass 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 →
GulfportILLINOIS32021
RichlandNEBRASKA22024
Gretna 2NEBRASKA22023
WainwrightOKLAHOMA21992
MelroseKANSAS11975
SeveranceKANSAS12010
GretnaNEBRASKA12017

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