BirdAnalyst
Species · Oregon · BBS 2025 Release · 1966–2024

Caspian Tern Population Trend in Oregon

All statesWetland birds

Caspian Tern in Oregon has edged down: down 11% on the route-weighted index since 1975.

-11%Since 1975
24Routes In State
44Years

Notable Caspian Tern Trends in Oregon

No notable trend signals for Caspian Tern in Oregon. See the full index history below.

Caspian Tern Population Forecast in Oregon

If the recent trend holds, Caspian Tern in Oregon is projected to stay roughly flat through 2029, near 0.10 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±496.8%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2029
0.10Projected 2029 index
0.00–0.4295% range
±496.8%Backtest error
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 index95% low95% high
20250.100.000.43
20260.100.000.43
20270.100.000.42
20280.100.000.42
20290.100.000.42

Caspian Tern Survey Routes in Oregon

Routes recording Caspian Tern in Oregon.
Harney Lake620011993
Glasgow420211989
Wedderburn320041971
Malheur Nwr219971986
Svensen219901990
Umatilla220221988
Monument219931993
Ordnance119751974
Nicolai Mtn.120141993
Fandango Can120162016
Buchanan120022002
Modoc Point120181988
Bly 2120222007
Sparta119961995
Princeton119851981
Hazel Camp120132001
Blizzard Gap120241987
Fish Lake120241984
Merrill120181995
Warner Vally120241994
Catlow Rim120131996
Chinchalo120151995
Lakeview120192019
Trout Creek120002000

Caspian Tern Population Trend in Other States

alabamaalaskacaliforniadelawarefloridaidahoillinoisindianalouisianamarylandmichiganminnesotamontananevadanorth-carolinanorth-dakotasouth-carolinatexasutahvermontvirginiawashingtonwisconsinwyoming

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