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

Black Tern In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieWetland birds

Black Tern in Central Mixed Grass Prairie has collapsed: down 84% on the route-weighted index since 1969.

-84%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 →
15Routes 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 →
52YearsYears 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 →

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 →

Black Tern has collapsed in Central Mixed Grass Prairie: down 84% on the route-weighted index since 1969.

Black Tern In Central Mixed Grass Prairie Population Forecast

If the recent trend holds, Black Tern in Central Mixed Grass Prairie is projected to fall about 32% by 2029 — from 0.06 in 2024 to a central estimate of 0.04 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±46.8%, with 100% of held-out values landing inside the 95% band.

-32%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 →
0.04Projected 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 →
0.00–0.7195% 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 →
±46.8%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, Black Tern in Central Mixed Grass Prairie is projected to fall about 32% by 2029 — from 0.06 in 2024 to a central estimate of 0.04 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±46.8%, 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 →
20250.070.000.73
20260.060.000.73
20270.050.000.72
20280.050.000.71
20290.040.000.71

Routes In Central Mixed Grass Prairie

Routes recording Black 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 →
MisslerKANSAS232003
Swan LakeNEBRASKA72022
Piester LakeNEBRASKA32018
KennedyNEBRASKA32021
BrownleeNEBRASKA22018
Wheeler CoNEBRASKA22024
NenzelNEBRASKA22019
CoatsKANSAS11997
AlbertKANSAS12021
SurpriseNEBRASKA11979
JohnstownNEBRASKA11969
TableNEBRASKA12003
GordonNEBRASKA12024
Crescent LkNEBRASKA12016
BassettNEBRASKA12024

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