Species · BCR 33 · BBS 2025 Release · 1966–2024

Caspian Tern In Sonoran and Mojave Deserts

All regions Sonoran and Mojave Deserts Wetland birds

Caspian Tern in Sonoran and Mojave Deserts has collapsed: down 90% on the route-weighted index since 1977.

-90%Since 1977

3Routes In Region

30Years

Notable Signals

long arc declinecomputed index

Caspian Tern has collapsed in Sonoran and Mojave Deserts: down 90% on the route-weighted index since 1977.

Forecast

If the recent trend holds, Caspian Tern in Sonoran and Mojave Deserts is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.64). A 5-year backtest shows a typical error of ±77.6%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2029

0.00Projected 2029 index

0.00–0.6495% range

±77.6%Backtest error

Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.

Year	Projected index	95% low	95% high
2025	0.00	0.00	0.64
2026	0.00	0.00	0.64
2027	0.00	0.00	0.64
2028	0.00	0.00	0.64
2029	0.00	0.00	0.64

Routes In Sonoran and Mojave Deserts

Routes recording Caspian Tern in Sonoran and Mojave Deserts.

Alamo River	CALIFORNIA	5	1986
Brawley	CALIFORNIA	2	2012
Niland	CALIFORNIA	1	2024

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