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

Anhinga Population Trend in Louisiana

All statesGeneralists

Anhinga in Louisiana has surged: up 160% on the route-weighted index since 1969.

+160%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 →
49Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Anhinga 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 →

Anhinga has surged in Louisiana: up 160% on the route-weighted index since 1969.

Anhinga Population Forecast in Louisiana

If the recent trend holds, Anhinga in Louisiana is projected to rise about 66% by 2029 — from 0.71 in 2024 to a central estimate of 1.2 (95% range 0.47–1.9). A 5-year backtest shows a typical error of ±92.2%, with 80% of held-out values landing inside the 95% band.

+66%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 →
1.2Projected 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 →
0.47–1.995% 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 →
±92.2%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, Anhinga in Louisiana is projected to rise about 66% by 2029 — from 0.71 in 2024 to a central estimate of 1.2 (95% range 0.47–1.9). A 5-year backtest shows a typical error of ±92.2%, with 80% 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 →
20251.10.411.8
20261.10.421.8
20271.10.441.9
20281.20.451.9
20291.20.471.9

Anhinga Survey Routes in Louisiana

Routes recording Anhinga 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 →
Ramah1520241989
Berwick1520181987
Fillmore919871968
Freetown520091995
Frogmore520231999
Goodwill420162016
Brousville320102010
Enterprise320192013
Port Allen320242000
River Road220241987
Atchafalaya220241989
Baton Rouge220231998
Shaw220241972
Rayville219991989
Esther220081988
Maurice220222004
Evelyn220222008
Forked Island220182010
Pearl River220221990
Fishville 2220192019
Natchitoches219891987
Haughton120142008
Morgan City119861975
Tensas Nwr120162001
Roseland119861986

Anhinga Population Trend in Other States

alabamaarkansasfloridageorgiamississippinorth-carolinaoklahomasouth-carolinatexasvirginia

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