BirdAnalyst
Species · BCR 23 · BBS 2025 Release · 1966–2024

Black Tern In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionWetland birds

Black Tern in Prairie Hardwood Transition has collapsed: down 93% on the route-weighted index since 1968.

-93%Since 1968TrendPercent 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 →
56Routes 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 →
58YearsYears 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 Prairie Hardwood Transition: down 93% on the route-weighted index since 1968.

Black Tern In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Black Tern in Prairie Hardwood Transition is projected to fall about 100% by 2029 — from 0.19 in 2024 to a central estimate of 0.00 (95% range 0.00–0.62). A 5-year backtest shows a typical error of ±171.7%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.6295% 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 →
±171.7%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, Black Tern in Prairie Hardwood Transition is projected to fall about 100% by 2029 — from 0.19 in 2024 to a central estimate of 0.00 (95% range 0.00–0.62). A 5-year backtest shows a typical error of ±171.7%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.000.000.62
20260.000.000.62
20270.000.000.62
20280.000.000.62
20290.000.000.62

Routes In Prairie Hardwood Transition

Routes recording Black Tern in Prairie Hardwood Transition.
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 →
Sherburne NrMINNESOTA112024
KnappMINNESOTA72024
OmroWISCONSIN72001
Big Blue LkMICHIGAN51990
Mount HorebWISCONSIN51986
MontereyMICHIGAN42008
AshbyMINNESOTA42016
PrincetonWISCONSIN41980
WeyerhauserWISCONSIN31981
KnoxINDIANA21993
RemusMICHIGAN21990
Money CreekMINNESOTA22011
St StephenMINNESOTA22005
Le CenterMINNESOTA22014
GraytownOHIO21973
HudsonWISCONSIN22003
DresserWISCONSIN22021
LoraineWISCONSIN22016
CumberlandWISCONSIN21988
ElderonWISCONSIN22001
Oconto FallsWISCONSIN22019
PardeevilleWISCONSIN21996
NashvilleMICHIGAN11970
GalesburgMICHIGAN11989
HowardsvilleMICHIGAN11982

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