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Species · Louisiana · BBS 2025 Release · 1966–2024

Purple Martin Population Trend in Louisiana

All statesAerial insectivores

Purple Martin in Louisiana has declined: down 25% on the route-weighted index since 1969.

-25%Since 1969TrendPercent 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 →
100Routes 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 →
57YearsYears 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 LouisianaNotable 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 Louisiana. See the full index history below.

Purple Martin Population Forecast in Louisiana

If the recent trend holds, Purple Martin in Louisiana is projected to fall about 48% by 2029 — from 32 in 2024 to a central estimate of 17 (95% range 2.9–31). A 5-year backtest shows a typical error of ±56.9%, with 100% of held-out values landing inside the 95% band.

-48%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 →
17Projected 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 →
2.9–3195% 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 →
±56.9%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 Louisiana is projected to fall about 48% by 2029 — from 32 in 2024 to a central estimate of 17 (95% range 2.9–31). A 5-year backtest shows a typical error of ±56.9%, with 100% of held-out values landing inside the 95% band.19672029
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 →
2025183.832
2026183.532
2027173.331
2028173.131
2029172.931

Purple Martin Survey Routes in Louisiana

Routes recording Purple Martin in Louisiana.
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 →
Ltl Chenier47120241986
Carlisle19519881968
Cypress13719871967
Morgan City12519861967
Hackberry 212420242018
River Road11520241987
Natchitoches10819911987
Forked Island 29420112010
Ltl Chenier 28320112010
Forked Island8320242008
Esther8120241988
Larose6919921988
Linville6520241998
Marion6219961988
Easton5919901967
Many5619921989
Longstreet5320241967
Keystone4920131967
Junior4719911987
Lafitte4219911967
Carterville3719921992
Gibson3720191999
Brousville3520241998
Berwick3420181987
Glencoe3320181988

Purple Martin Population Trend in Other States

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

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