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Species · Louisiana · BBS 2025 Release · 1966–2024

Pied-billed Grebe Population Trend in Louisiana

All statesWetland birds

Pied-billed Grebe in Louisiana has increased: up 47% on the route-weighted index since 1988.

+47%Since 1988TrendPercent 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 →
26Routes 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 →
34YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pied-billed Grebe 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 Pied-billed Grebe in Louisiana. See the full index history below.

Pied-billed Grebe Population Forecast in Louisiana

If the recent trend holds, Pied-billed Grebe in Louisiana is projected to fall about 41% by 2029 — from 0.49 in 2024 to a central estimate of 0.29 (95% range 0.00–0.64). A 5-year backtest shows a typical error of ±119.3%, 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 →
0.29Projected 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 →
0.00–0.6495% 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 →
±119.3%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, Pied-billed Grebe in Louisiana is projected to fall about 41% by 2029 — from 0.49 in 2024 to a central estimate of 0.29 (95% range 0.00–0.64). A 5-year backtest shows a typical error of ±119.3%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.280.000.63
20260.280.000.63
20270.280.000.63
20280.290.000.64
20290.290.000.64

Pied-billed Grebe Survey Routes in Louisiana

Routes recording Pied-billed Grebe 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 →
Maurice1720241988
Richard720182009
Ltl Chenier520231988
Keystone420082000
Shaw420141987
Vinton 2320232011
Esther320242007
Sabine Nwr319931993
Creole219751975
De Ridder220032003
Forked Island 2220112011
Forked Island220172010
Ville Platte220162008
Delhi220192015
Tensas Nwr120192019
Atchafalaya120012001
Baton Rouge120212010
Ivan120062000
Hackberry120132013
Ramah120081994
Kaplan120232001
Woodlawn120212008
Port Allen120132001
Sabine Nwr 2120122012
Natchez120121997

Pied-billed Grebe Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwisconsinwyoming

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