BirdAnalyst
Species · BCR 11 · BBS 2025 Release · 1966–2024

Common Tern In Prairie Potholes

All regionsPrairie PotholesWetland birds

Common Tern in Prairie Potholes has surged: up 86% on the route-weighted index since 1980.

+86%Since 1980TrendPercent 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 →
25Routes 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 →
40YearsYears 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 increasecomputed 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 surged in Prairie Potholes: up 86% on the route-weighted index since 1980.

Forecast

If the recent trend holds, Common Tern in Prairie Potholes is projected to rise about 29% by 2029 — from 0.18 in 2024 to a central estimate of 0.24 (95% range 0.00–0.48). A 5-year backtest shows a typical error of ±179.4%, with 100% of held-out values landing inside the 95% band.

+29%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 →
0.24Projected 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 →
0.00–0.4895% 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 →
±179.4%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 Potholes is projected to rise about 29% by 2029 — from 0.18 in 2024 to a central estimate of 0.24 (95% range 0.00–0.48). A 5-year backtest shows a typical error of ±179.4%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.220.000.47
20260.230.000.47
20270.230.000.47
20280.230.000.48
20290.240.000.48

Routes In Prairie Potholes

Routes recording Common Tern in Prairie Potholes.
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 →
Horsehead LkNORTH-DAKOTA122024
EmeradoNORTH-DAKOTA81997
BraddockNORTH-DAKOTA81989
CourtlandMINNESOTA31991
BadgerMINNESOTA31990
Ester LakeMONTANA32016
MontpelierNORTH-DAKOTA32022
Great FallsMONTANA22003
Lake GeorgeNORTH-DAKOTA22004
NilesNORTH-DAKOTA21993
Douglas CrkNORTH-DAKOTA22018
VeblenSOUTH-DAKOTA21973
ChokioMINNESOTA11987
VirgelleMONTANA11990
ClevelandMONTANA12013
ChinookMONTANA12018
DanzigNORTH-DAKOTA12014
BuchananNORTH-DAKOTA12015
ReganNORTH-DAKOTA11998
StanleyNORTH-DAKOTA11992
Wild RoseNORTH-DAKOTA12023
Powers LakeNORTH-DAKOTA12024
ParshallNORTH-DAKOTA11993
Sheyenne LkNORTH-DAKOTA12009
Turtle MtnsNORTH-DAKOTA12004

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