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Species · Louisiana · BBS 2026 Release · 1966–2025

Purple Gallinule Population Trend in Louisiana

All statesWetland birds

Purple Gallinule in Louisiana has surged: up 169% on the route-weighted index since 1970.

+169%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 →
20Routes 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 →
41YearsYears 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 Gallinule 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 →

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 Gallinule has surged in Louisiana: up 169% on the route-weighted index since 1970.

Purple Gallinule Population Forecast in Louisiana

If the recent trend holds, Purple Gallinule in Louisiana is projected to fall about 70% by 2030 — from 0.61 in 2025 to a central estimate of 0.18 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±49.3%, with 80% of held-out values landing inside the 95% band.

-70%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 →
0.18Projected 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 →
0.00–0.4995% 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 →
±49.3%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 Gallinule in Louisiana is projected to fall about 70% by 2030 — from 0.61 in 2025 to a central estimate of 0.18 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±49.3%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.180.000.49
20270.180.000.49
20280.180.000.49
20290.180.000.49
20300.180.000.49

Purple Gallinule Survey Routes in Louisiana

Routes recording Purple Gallinule 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 Chenier1520251986
Forked Island720252008
Forked Island 2620102010
Mamou419801967
Ramah220252012
Morgan City220142013
Hackberry 2220182018
Gran Chenier119821980
Atchafalaya120151998
Easton119701970
Hackberry119981976
Shaw120222022
Glencoe119891989
Esther120242004
Maurice119951994
Kaplan120221998
Port Allen120132005
Richard119981998
Sabine Nwr 2120122012
Sabine Nwr120041989

Purple Gallinule Population Trend in Other States

alabamaarkansasfloridageorgiamississippitexas

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