BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Anhinga In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainGeneralists

Anhinga in Southeastern Coastal Plain has surged: up 141% on the route-weighted index since 1968.

+141%Since 1968TrendPercent 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 →
140Routes 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 →
58YearsYears 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 →

Anhinga has surged in Southeastern Coastal Plain: up 141% on the route-weighted index since 1968.

Anhinga In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Anhinga in Southeastern Coastal Plain is projected to stay roughly flat through 2029, near 0.28 (95% range 0.11–0.45). A 5-year backtest shows a typical error of ±34.3%, with 60% of held-out values landing inside the 95% band.

+6%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 →
0.28Projected 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 →
0.11–0.4595% 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 →
±34.3%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, Anhinga in Southeastern Coastal Plain is projected to stay roughly flat through 2029, near 0.28 (95% range 0.11–0.45). A 5-year backtest shows a typical error of ±34.3%, with 60% of held-out values landing inside the 95% band.19662029
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 →
20250.270.100.43
20260.270.100.44
20270.270.100.44
20280.280.110.45
20290.280.110.45

Routes In Southeastern Coastal Plain

Routes recording Anhinga in Southeastern Coastal Plain.
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 →
DarienGEORGIA362019
BennettsvilleSOUTH-CAROLINA212017
RiceboroGEORGIA142006
OwensboroGEORGIA102023
LovedaleFLORIDA62011
Fort AdamsMISSISSIPPI61997
MadridALABAMA42019
BlackwaterFLORIDA41989
NewtonGEORGIA42024
ShilohGEORGIA42024
StarMISSISSIPPI42021
FitzgeraldGEORGIA32024
PineoraGEORGIA32017
WeberGEORGIA32024
NixvilleSOUTH-CAROLINA32009
WallsboroALABAMA22004
FairviewALABAMA22024
Broad BranchFLORIDA22023
HilliardFLORIDA22013
Defuniak SprFLORIDA22022
CallahanFLORIDA22023
Harrietts BlGEORGIA22023
BaxleyGEORGIA22019
WrightsvilleGEORGIA22015
HawkinsvilleGEORGIA22024

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