BirdAnalyst
Species · BCR 5 · BBS 2026 Release · 1966–2025

Caspian Tern In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestWetland birds

Caspian Tern in Northern Pacific Rainforest has edged up: up 11% on the route-weighted index since 1975.

+11%Since 1975TrendPercent 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 →
51YearsYears 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 Northern Pacific Rainforest. See the full index history below.

Caspian Tern In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Caspian Tern in Northern Pacific Rainforest is projected to rise about 417% by 2030 — from 0.07 in 2025 to a central estimate of 0.37 (95% range 0.00–0.73). A 5-year backtest shows a typical error of ±255.4%, with 80% of held-out values landing inside the 95% band.

+417%Change by 2030TrendPercent 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 →
0.37Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.7395% 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 →
±255.4%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, Caspian Tern in Northern Pacific Rainforest is projected to rise about 417% by 2030 — from 0.07 in 2025 to a central estimate of 0.37 (95% range 0.00–0.73). A 5-year backtest shows a typical error of ±255.4%, with 80% of held-out values landing inside the 95% band.19682030
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 →
20260.350.000.72
20270.360.000.72
20280.360.000.73
20290.360.000.73
20300.370.000.73

Routes In Northern Pacific Rainforest

Routes recording Caspian Tern in Northern Pacific Rainforest.
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 →
HoneydewCALIFORNIA42011
GlasgowOREGON42021
Port AngelesWASHINGTON42023
McchordWASHINGTON41998
WedderburnOREGON32004
Bunker HillWASHINGTON32000
MukilteoWASHINGTON32025
Warm Beach 2WASHINGTON32024
YakutatALASKA22023
Fish RockCALIFORNIA22013
SvensenOREGON21990
Warm BeachWASHINGTON22017
IlwacoWASHINGTON22025
South ElmaWASHINGTON21990
DeceptionWASHINGTON21997
MccloudCALIFORNIA11980
Bodega BayCALIFORNIA12019
YrekaCALIFORNIA12006
Hazel CampOREGON12013
Nicolai Mtn.OREGON12014
TaholahWASHINGTON12017
RaymondWASHINGTON12018
Vashon Is.WASHINGTON12023

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.