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

Purple Martin Population Trend in Alabama

All statesAerial insectivores

Purple Martin in Alabama has fallen sharply: down 51% on the route-weighted index since 1968.

-51%Since 1968TrendPercent 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 →
108Routes 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 →
58YearsYears 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 AlabamaNotable 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 fallen sharply in Alabama: down 50% on the route-weighted index since 1968.

Purple Martin Population Forecast in Alabama

If the recent trend holds, Purple Martin in Alabama is projected to fall about 41% by 2029 — from 12 in 2024 to a central estimate of 7.2 (95% range 0.00–15). A 5-year backtest shows a typical error of ±18.7%, with 100% of held-out values landing inside the 95% band.

-41%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 →
7.2Projected 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 →
0.00–1595% 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 →
±18.7%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 Alabama is projected to fall about 41% by 2029 — from 12 in 2024 to a central estimate of 7.2 (95% range 0.00–15). A 5-year backtest shows a typical error of ±18.7%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20258.40.4416
20268.10.1316
20277.80.0016
20287.50.0016
20297.20.0015

Purple Martin Survey Routes in Alabama

Routes recording Purple Martin in Alabama.
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 →
Grangeburg7420241966
Liberty5520221966
Brundidge5220211966
Elamville4820241984
Fairview4620241989
Mclellan4520241966
Rock Chapel3820241996
Dearmanville3719801967
Wedowee3520231996
Foley3419841966
Latham 23320242005
Nixburg 22720242000
Holt2620231993
Summitt2519811966
Eufaula2520241996
Woodville2420241994
Valhermoso Spgs2220101967
Liberty City 22220242017
Wedgeworth2120241979
Whitehall2120241983
Alabama Pt1820031966
Lakeview1820241999
Jasper1819991996
Millry1720181970
Riverside1720131999

Purple Martin Population Trend in Other States

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

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