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

Common Tern In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionWetland birds

Common Tern in Prairie Hardwood Transition has collapsed: down 90% on the route-weighted index since 1970.

-90%Since 1970TrendPercent 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 →
8Routes 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 →
18YearsYears 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 →

Common Tern has collapsed in Prairie Hardwood Transition: down 90% on the route-weighted index since 1970.

Common Tern In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Common Tern in Prairie Hardwood Transition is projected to stay roughly flat through 2024, near 0.00 (95% range 0.00–0.11). A 5-year backtest shows a typical error of ±682.6%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2024TrendPercent 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 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1195% 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 →
±682.6%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, Common Tern in Prairie Hardwood Transition is projected to stay roughly flat through 2024, near 0.00 (95% range 0.00–0.11). A 5-year backtest shows a typical error of ±682.6%, with 100% of held-out values landing inside the 95% band.19672024
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 →
20200.000.000.11
20210.000.000.11
20220.000.000.11
20230.000.000.11
20240.000.000.11

Routes In Prairie Hardwood Transition

Routes recording Common 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 →
PackertownINDIANA21977
HamtramckMICHIGAN21984
EdwardsMINNESOTA21983
GraytownOHIO21981
Packertown 2INDIANA12017
Indiana DuneINDIANA12019
DeckervilleMICHIGAN11994
OmroWISCONSIN11980

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