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

Purple Martin Population Trend in Indiana

All statesAerial insectivores

Purple Martin in Indiana has increased: up 38% on the route-weighted index since 1968.

+38%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 →
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 IndianaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Purple Martin in Indiana. See the full index history below.

Purple Martin Population Forecast in Indiana

If the recent trend holds, Purple Martin in Indiana is projected to fall about 51% by 2029 — from 8.8 in 2024 to a central estimate of 4.3 (95% range 1.2–7.5). A 5-year backtest shows a typical error of ±44.8%, with 60% of held-out values landing inside the 95% band.

-51%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 →
4.3Projected 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 →
1.2–7.595% 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 →
±44.8%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 51% by 2029 — from 8.8 in 2024 to a central estimate of 4.3 (95% range 1.2–7.5). A 5-year backtest shows a typical error of ±44.8%, with 60% 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 →
20254.41.37.6
20264.41.37.6
20274.41.37.5
20284.41.27.5
20294.31.27.5

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 →
Middlebury6120241989
Newberry4020242002
Brookville3920241966
Packertown3620041967
Decatur2920242000
Wabash2720241981
Lagrange2720241999
Berne2620241966
Vevay2520241966
Celestine2320241979
Cross Plains1620242007
Packertown 21620242005
Spencer1220241967
New Phila1120241982
Scottsburg1120241982
Fowler1020241966
Indian Spgs1020241982
Columbia Cty820221981
Milroy820241966
Clear Spring820241981
Corydon820241966
Cuba820242017
Georgia820241999
Thorntown620241982
Azalia620241982

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 2026-05-22.