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

Purple Martin In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsAerial insectivores

Purple Martin in Sonoran and Mojave Deserts has collapsed: down 92% on the route-weighted index since 1977.

-92%Since 1977TrendPercent 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 →
6Routes 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 →
22YearsYears 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 →

Purple Martin has collapsed in Sonoran and Mojave Deserts: down 91% on the route-weighted index since 1977.

Forecast

If the recent trend holds, Purple Martin in Sonoran and Mojave Deserts is projected to stay roughly flat through 2024, near 0.00 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±739.8%, with 0% of held-out values landing inside the 95% band.

n/aChange by 2024TrendPercent 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 →
0.00Projected 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4595% 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 →
±739.8%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, Purple Martin in Sonoran and Mojave Deserts is projected to stay roughly flat through 2024, near 0.00 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±739.8%, with 0% of held-out values landing inside the 95% band.19752024
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 →
20200.000.000.45
20210.000.000.45
20220.000.000.45
20230.000.000.45
20240.000.000.45

Routes In Sonoran and Mojave Deserts

Routes recording Purple Martin 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 →
LukevilleARIZONA71981
Red RockARIZONA42001
Organ PipeARIZONA41994
Cutter 2ARIZONA22018
Casa GrandeARIZONA12003
Ajo 2ARIZONA12019

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