BirdAnalyst
Species · Arizona · BBS 2025 Release · 1966–2024

Purple Martin Population Trend in Arizona

All statesAerial insectivores

Purple Martin in Arizona has surged: up 401% on the route-weighted index since 1970.

+401%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 →
30Routes In StateSurvey 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 Purple Martin Trends in ArizonaNotable 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 Arizona: up 401% on the route-weighted index since 1970.

Purple Martin Population Forecast in Arizona

If the recent trend holds, Purple Martin in Arizona is projected to rise about 44% by 2029 — from 1.0 in 2024 to a central estimate of 1.4 (95% range 0.00–3.5). A 5-year backtest shows a typical error of ±28%, with 100% of held-out values landing inside the 95% band.

+44%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 →
1.4Projected 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 →
0.00–3.595% 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 →
±28%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 Arizona is projected to rise about 44% by 2029 — from 1.0 in 2024 to a central estimate of 1.4 (95% range 0.00–3.5). A 5-year backtest shows a typical error of ±28%, with 100% 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 →
20251.40.003.5
20261.40.003.5
20271.40.003.5
20281.40.003.5
20291.40.003.5

Purple Martin Survey Routes in Arizona

Routes recording Purple Martin in Arizona.
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 →
Alpine1620232017
Forest Lakes1420241992
Redington1420231993
Pinetop1320222014
Happy Jack1220241977
Sawmill1120141989
Tonto Vill.1120212001
Pomerene920241968
Lukeville719811975
Sprucedale620231992
Portal519791978
Sahuarita520231993
Organ Pipe419941990
Red Rock420011995
Prescott220121977
Hunt219761976
Aztec Peak219781978
Blue219891974
Patagonia219811981
Cutter 2220182015
Williams220192006
Cutter220002000
Flagstaff120222022
Mormon Lake119751975
Zeniff119721972

Purple Martin Population Trend in Other States

alabamaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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