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

Caspian Tern In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionWetland birds

Caspian Tern in Prairie Hardwood Transition has edged down: down 18% on the route-weighted index since 1985.

-18%Since 1985TrendPercent 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 →
16Routes 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 →
26YearsYears 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 Caspian Tern in Prairie Hardwood Transition. See the full index history below.

Caspian Tern In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Caspian Tern in Prairie Hardwood Transition is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±62.1%, 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 →
0.00–0.0795% 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 →
±62.1%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, Caspian Tern in Prairie Hardwood Transition is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±62.1%, with 100% of held-out values landing inside the 95% band.19732029
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 →
20250.020.000.07
20260.020.000.07
20270.020.000.07
20280.020.000.07
20290.020.000.07

Routes In Prairie Hardwood Transition

Routes recording Caspian 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 →
EdwardsMINNESOTA31987
GalesburgMICHIGAN21973
No BradleyMICHIGAN22012
AdrianMICHIGAN22017
Le CenterMINNESOTA22011
Indiana DuneINDIANA12024
Big Blue LkMICHIGAN12013
RemusMICHIGAN12007
HartlandMICHIGAN11993
MinnetonkaMINNESOTA11996
PrincetonMINNESOTA12001
OsseoMINNESOTA11992
KnappMINNESOTA11992
St StephenMINNESOTA11993
EvergreenMINNESOTA11990
CascoWISCONSIN12017

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