BirdAnalyst
Species · BCR 34 · BBS 2026 Release · 1966–2025

Purple Martin In Sierra Madre Occidental

All regionsSierra Madre OccidentalAerial insectivores

Purple Martin in Sierra Madre Occidental has surged: up 202% on the route-weighted index since 1970.

+202%Since 1970TrendPercent 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 →
24Routes 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 →
56YearsYears 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 →

Purple Martin has surged in Sierra Madre Occidental: up 202% on the route-weighted index since 1970.

Purple Martin In Sierra Madre Occidental Population Forecast

If the recent trend holds, Purple Martin in Sierra Madre Occidental is projected to fall about 33% by 2030 — from 4.9 in 2025 to a central estimate of 3.2 (95% range 0.08–6.4). A 5-year backtest shows a typical error of ±32.6%, with 100% of held-out values landing inside the 95% band.

-33%Change by 2030TrendPercent 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 →
3.2Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.08–6.495% 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 →
±32.6%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, Purple Martin in Sierra Madre Occidental is projected to fall about 33% by 2030 — from 4.9 in 2025 to a central estimate of 3.2 (95% range 0.08–6.4). A 5-year backtest shows a typical error of ±32.6%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20263.20.016.3
20273.20.036.3
20283.20.056.4
20293.20.066.4
20303.20.086.4

Routes In Sierra Madre Occidental

Routes recording Purple Martin in Sierra Madre Occidental.
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 →
AlpineARIZONA352025
Happy JackARIZONA252025
PomereneARIZONA232025
RedingtonARIZONA202025
PinetopARIZONA132022
SprucedaleARIZONA92025
WilliamsARIZONA62025
Tonto Vill.ARIZONA62025
PortalARIZONA51979
SahuaritaARIZONA32025
ReserveNEW-MEXICO32025
Emory PassNEW-MEXICO32007
PrescottARIZONA22012
Aztec PeakARIZONA21978
BlueARIZONA21989
PatagoniaARIZONA21981
CutterARIZONA22000
FlagstaffARIZONA12022
Mormon LakeARIZONA11975
Peña BlancaARIZONA11994
Forest LakesARIZONA12025
AmadoARIZONA12018
Carr MtnARIZONA12000
MagdalenaNEW-MEXICO12013

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.