BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Black Tern In Great Basin

All regionsGreat BasinWetland birds

Black Tern in Great Basin has collapsed: down 92% on the route-weighted index since 1970.

-92%Since 1970
41Routes In Region
56Years

Notable Signals

long arc declinecomputed index

Black Tern has collapsed in Great Basin: down 92% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Black Tern in Great Basin is projected to fall about 19% by 2029 — from 0.12 in 2024 to a central estimate of 0.10 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±318.7%, with 100% of held-out values landing inside the 95% band.

-19%Change by 2029
0.10Projected 2029 index
0.00–0.7195% range
±318.7%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
20250.130.000.74
20260.120.000.73
20270.110.000.72
20280.110.000.72
20290.100.000.71

Routes In Great Basin

Routes recording Black Tern in Great Basin.
Warner VallyOREGON352007
Catlow RimOREGON202016
Fish LakeOREGON172024
Clear Lk ResCALIFORNIA132004
Blizzard GapOREGON122005
BlyOREGON102001
Bald Mtn.NEVADA82013
ChinchaloOREGON72021
HenryIDAHO61978
DorrisCALIFORNIA52017
Barnes ValOREGON51987
Harney LakeOREGON42003
MaldenWASHINGTON42012
Turnbull NwrWASHINGTON42021
Crowley LakeCALIFORNIA31982
Crowder FlatCALIFORNIA32019
MadelineCALIFORNIA32022
BrewsterWASHINGTON32000
RavendaleCALIFORNIA21979
MacdoelCALIFORNIA22005
SpringfieldIDAHO21973
Dell SpringOREGON21976
Modoc PointOREGON22002
Moses LakeWASHINGTON21990
EwanWASHINGTON22019

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