BirdAnalyst
Species · Indiana · BBS 2026 Release · 1966–2025

Purple Martin Population Trend in Indiana

All statesAerial insectivores

Purple Martin in Indiana has surged: up 76% on the route-weighted index since 1968.

+76%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 →
64Routes 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 →
59YearsYears 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 IndianaNotable 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 Indiana: up 76% on the route-weighted index since 1968.

Purple Martin Population Forecast in Indiana

If the recent trend holds, Purple Martin in Indiana is projected to fall about 58% by 2030 — from 12 in 2025 to a central estimate of 4.9 (95% range 1.3–8.5). A 5-year backtest shows a typical error of ±46.8%, with 60% of held-out values landing inside the 95% band.

-58%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 →
4.9Projected 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 →
1.3–8.595% 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 →
±46.8%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 Indiana is projected to fall about 58% by 2030 — from 12 in 2025 to a central estimate of 4.9 (95% range 1.3–8.5). A 5-year backtest shows a typical error of ±46.8%, with 60% of held-out values landing inside the 95% band.19662030
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 →
20264.91.38.5
20274.91.38.5
20284.91.38.5
20294.91.38.5
20304.91.38.5

Purple Martin Survey Routes in Indiana

Routes recording Purple Martin in Indiana.
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 →
Decatur8720252000
New Phila4420251982
Wabash4220251981
Middlebury3820251989
Packertown3620041967
Packertown 23420252005
Indian Spgs2820251982
Witts Station2720252000
Washington2020251987
Newberry2020252002
Lagrange1920251999
Pimento1720251981
Thorntown1620251982
Vevay1620251966
Cross Plains1620242007
Georgia1420251999
Spencer1220241967
Brookville1120251966
Fowler1020241966
Celestine1020251979
Scottsburg1020251982
Cuba1020252017
Berne920251966
Clear Spring920251981
Columbia Cty820221981

Purple Martin Population Trend in Other States

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

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