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

Great Horned Owl In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

Great Horned Owl in Sonoran and Mojave Deserts has surged: up 99% on the route-weighted index since 1972.

+99%Since 1972TrendPercent 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 →
46Routes 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 →
54YearsYears 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 increasecomputed 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 →

Great Horned Owl has surged in Sonoran and Mojave Deserts: up 99% on the route-weighted index since 1972.

Forecast

If the recent trend holds, Great Horned Owl in Sonoran and Mojave Deserts is projected to rise about 259% by 2029 — from 0.13 in 2024 to a central estimate of 0.48 (95% range 0.19–0.77). A 5-year backtest shows a typical error of ±75.6%, with 60% of held-out values landing inside the 95% band.

+259%Change 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 →
0.48Projected 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 →
0.19–0.7795% 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 →
±75.6%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, Great Horned Owl in Sonoran and Mojave Deserts is projected to rise about 259% by 2029 — from 0.13 in 2024 to a central estimate of 0.48 (95% range 0.19–0.77). A 5-year backtest shows a typical error of ±75.6%, with 60% of held-out values landing inside the 95% band.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 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 →
20250.460.170.75
20260.460.170.75
20270.470.180.76
20280.470.180.76
20290.480.190.77

Routes In Sonoran and Mojave Deserts

Routes recording Great Horned Owl 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 →
Joshua TreeCALIFORNIA61998
Casa GrandeARIZONA42023
Ajo 2ARIZONA42019
DatelandARIZONA32021
Cabeza PrietARIZONA32019
WickenburgARIZONA32022
HopeARIZONA31992
Imperial DamCALIFORNIA31988
QuartzsiteARIZONA22015
Gila BendARIZONA22022
Palo VerdeARIZONA22013
ArabyARIZONA22022
Organ PipeARIZONA22022
Cutter 2ARIZONA22018
Hope 2ARIZONA22018
WildroseCALIFORNIA21992
NilandCALIFORNIA22018
PearblossomCALIFORNIA21991
NelsonNEVADA22024
WikieupARIZONA12024
New RiverARIZONA12014
FlorenceARIZONA11988
LagunaARIZONA12018
AjoARIZONA11970
CoolidgeARIZONA11984

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