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.

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.