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Species · BCR 2 · BBS 2025 Release · 1966–2024

Arctic Tern In BCR 2

All regionsBCR 2Wetland birds

Arctic Tern in BCR 2 has increased: up 45% on the route-weighted index since 1985.

+45%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 →
23Routes 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 →

No notable trend signals for Arctic Tern in BCR 2. See the full index history below.

Arctic Tern In BCR 2 Population Forecast

If the recent trend holds, Arctic Tern in BCR 2 is projected to rise about 132% by 2029 — from 4.8 in 2024 to a central estimate of 11 (95% range 0.00–26). A 5-year backtest shows a typical error of ±566.8%, with 80% of held-out values landing inside the 95% band.

+132%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 →
11Projected 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 →
0.00–2695% 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 →
±566.8%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 2 is projected to rise about 132% by 2029 — from 4.8 in 2024 to a central estimate of 11 (95% range 0.00–26). A 5-year backtest shows a typical error of ±566.8%, with 80% of held-out values landing inside the 95% band.19832029
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 →
2025110.0025
2026110.0025
2027110.0025
2028110.0026
2029110.0026

Routes In BCR 2

Routes recording Arctic Tern in BCR 2.
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 →
Goodnews BayALASKA632005
Kanektok RivALASKA482005
Cape NomeALASKA342024
Togiak RiverALASKA262005
NomeALASKA112023
Cold BayALASKA62024
Cold Bay (Short)ALASKA51991
KodiakALASKA31983
Kodiak 2ALASKA32019
St. Mary'SALASKA31994
Kugarak (Short)ALASKA31987
Katmai N.P.ALASKA22000
Gweek RiverALASKA22002
TupuknukALASKA21995
Selawik (Short)ALASKA21987
ChiniakALASKA12024
DillinghamALASKA12019
King SalmonALASKA12024
CouncilALASKA12010
Salmon LakeALASKA12023
TellerALASKA12009
KotzebueALASKA12024
Kotzebue (Short)ALASKA11994

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