BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Pied-billed Grebe In Gulf Coastal Prairie

All regionsGulf Coastal PrairieWetland birds

Pied-billed Grebe in Gulf Coastal Prairie has surged: up 554% on the route-weighted index since 1975.

+554%Since 1975TrendPercent 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 →
31Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
40YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Pied-billed Grebe has surged in Gulf Coastal Prairie: up 554% on the route-weighted index since 1975.

Pied-billed Grebe In Gulf Coastal Prairie Population Forecast

If the recent trend holds, Pied-billed Grebe in Gulf Coastal Prairie is projected to fall about 35% by 2029 — from 1.2 in 2024 to a central estimate of 0.80 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±209.9%, with 100% of held-out values landing inside the 95% band.

-35%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 →
0.80Projected 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 →
0.00–1.795% 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 →
±209.9%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, Pied-billed Grebe in Gulf Coastal Prairie is projected to fall about 35% by 2029 — from 1.2 in 2024 to a central estimate of 0.80 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±209.9%, 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 →
20250.770.001.6
20260.770.001.6
20270.780.001.7
20280.790.001.7
20290.800.001.7

Routes In Gulf Coastal Prairie

Routes recording Pied-billed Grebe in Gulf Coastal Prairie.
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 →
MauriceLOUISIANA172024
RichardLOUISIANA72018
Loyola Beach 2TEXAS62016
Ltl ChenierLOUISIANA52023
WinnieTEXAS41994
KatyTEXAS42024
Rock IslandTEXAS42015
EstherLOUISIANA32024
Sabine NwrLOUISIANA31993
Vinton 2LOUISIANA32023
San PedroTEXAS31998
Goliad PrairieTEXAS32007
CreoleLOUISIANA21975
Ville PlatteLOUISIANA22016
Forked IslandLOUISIANA22017
Forked Island 2LOUISIANA22011
IndianolaTEXAS22024
DanburyTEXAS22019
Loyola BeachTEXAS22008
Oyster LakeTEXAS22019
L. Atascosa NwrTEXAS22023
HackberryLOUISIANA12013
KaplanLOUISIANA12023
Sabine Nwr 2LOUISIANA12012
WoodlawnLOUISIANA12021

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