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

Swainson's Hawk In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

Swainson's Hawk in Sonoran and Mojave Deserts has fallen sharply: down 54% on the route-weighted index since 1975.

-54%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 →
15Routes 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 →
28YearsYears 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 →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Swainson's Hawk has fallen sharply in Sonoran and Mojave Deserts: down 54% on the route-weighted index since 1975.

Swainson's Hawk In Sonoran and Mojave Deserts Population Forecast

If the recent trend holds, Swainson's Hawk in Sonoran and Mojave Deserts is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±168.9%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent 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 →
0.07Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1795% 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 →
±168.9%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, Swainson's Hawk in Sonoran and Mojave Deserts is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±168.9%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.070.000.17
20260.070.000.17
20270.070.000.17
20280.070.000.17
20290.070.000.17

Routes In Sonoran and Mojave Deserts

Routes recording Swainson's Hawk in Sonoran and Mojave Deserts.
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 →
DatelandARIZONA42016
CoolidgeARIZONA21982
Parker DamCALIFORNIA21975
GlamisCALIFORNIA21974
AntaresARIZONA12024
Red RockARIZONA12011
Cabeza PrietARIZONA11996
HopeARIZONA11996
Cactus ForestARIZONA12022
Cutter 2ARIZONA12018
Haiwee ResCALIFORNIA11999
Calif CityCALIFORNIA11980
Anza BorregoCALIFORNIA12011
BlytheCALIFORNIA11976
AlamoNEVADA11970

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