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Species · BCR 3 · BBS 2025 Release · 1966–2024

Arctic Tern In BCR 3

All regionsBCR 3Wetland birds

Arctic Tern in BCR 3 has increased: up 33% on the route-weighted index since 1995.

+33%Since 1995TrendPercent 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 →
4Routes 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 →
27YearsYears 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 Arctic Tern in BCR 3. See the full index history below.

Arctic Tern In BCR 3 Population Forecast

If the recent trend holds, Arctic Tern in BCR 3 is projected to rise about 61% by 2029 — from 0.50 in 2024 to a central estimate of 0.80 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±26.6%, with 100% of held-out values landing inside the 95% band.

+61%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 →
0.80Projected 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 →
0.00–1.695% 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 →
±26.6%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, Arctic Tern in BCR 3 is projected to rise about 61% by 2029 — from 0.50 in 2024 to a central estimate of 0.80 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±26.6%, with 100% of held-out values landing inside the 95% band.19932029
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 →
20250.810.001.7
20260.810.001.7
20270.800.001.6
20280.800.001.6
20290.800.001.6

Routes In BCR 3

Routes recording Arctic Tern in BCR 3.
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 →
UtqiagvikALASKA22022
Galbraith L.ALASKA22022
Red DogALASKA22024
Dietrich CmpALASKA12011

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