BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Caspian Tern In Coastal California

All regionsCoastal CaliforniaWetland birds

Caspian Tern in Coastal California has edged down: down 20% on the route-weighted index since 1970.

-20%Since 1970
31Routes In Region
55Years

Notable Signals

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

Forecast

If the recent trend holds, Caspian Tern in Coastal California is projected to rise about 51% by 2029 — from 0.38 in 2024 to a central estimate of 0.58 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±1436.4%, with 100% of held-out values landing inside the 95% band.

+51%Change by 2029
0.58Projected 2029 index
0.00–1.695% range
±1436.4%Backtest error
19682029
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
20250.550.001.5
20260.560.001.5
20270.570.001.5
20280.570.001.6
20290.580.001.6

Routes In Coastal California

Routes recording Caspian Tern in Coastal California.
Harbor Lake 2CALIFORNIA152024
AdelaidaCALIFORNIA81992
ColmaCALIFORNIA61972
CollegevilleCALIFORNIA21977
Foster ParkCALIFORNIA21974
S CatalinaCALIFORNIA22017
WestleyCALIFORNIA22018
MoragaCALIFORNIA22019
Buena VistaCALIFORNIA22019
PenningtonCALIFORNIA11978
RiovistaCALIFORNIA12024
HughsonCALIFORNIA12010
Harbor LakeCALIFORNIA11989
MorenoCALIFORNIA12017
San YsidroCALIFORNIA12017
HollisterCALIFORNIA12006
Lake SuccessCALIFORNIA11981
Morro BayCALIFORNIA11993
Point ReyesCALIFORNIA12021
FairfaxCALIFORNIA12024
PowayCALIFORNIA11980
ShafterCALIFORNIA11987
GlennCALIFORNIA11993
AtwaterCALIFORNIA11986
OrovilleCALIFORNIA12009

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