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Species · BCR 26 · BBS 2025 Release · 1966–2024

Anhinga In Mississippi Alluvial Valley

All regionsMississippi Alluvial ValleyGeneralists

Anhinga in Mississippi Alluvial Valley has surged: up 682% on the route-weighted index since 1974.

+682%Since 1974TrendPercent 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 →
35Routes 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 →
48YearsYears 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 Mississippi Alluvial Valley: up 682% on the route-weighted index since 1974.

Anhinga In Mississippi Alluvial Valley Population Forecast

If the recent trend holds, Anhinga in Mississippi Alluvial Valley is projected to rise about 56% by 2029 — from 1.1 in 2024 to a central estimate of 1.7 (95% range 0.79–2.6). A 5-year backtest shows a typical error of ±85.1%, with 60% of held-out values landing inside the 95% band.

+56%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 →
1.7Projected 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 →
0.79–2.695% 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 →
±85.1%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 Mississippi Alluvial Valley is projected to rise about 56% by 2029 — from 1.1 in 2024 to a central estimate of 1.7 (95% range 0.79–2.6). A 5-year backtest shows a typical error of ±85.1%, with 60% of held-out values landing inside the 95% band.19692029
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 →
20251.60.682.5
20261.60.712.5
20271.60.742.6
20281.70.762.6
20291.70.792.6

Routes In Mississippi Alluvial Valley

Routes recording Anhinga in Mississippi Alluvial Valley.
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 →
RamahLOUISIANA152024
BerwickLOUISIANA152018
Tchula 2MISSISSIPPI61994
FreetownLOUISIANA52009
FrogmoreLOUISIANA52023
Eagle LakeMISSISSIPPI52024
Tchula 3MISSISSIPPI42024
BrousvilleLOUISIANA32010
Port AllenLOUISIANA32024
EudoraARKANSAS21997
ShawLOUISIANA22024
RayvilleLOUISIANA21999
River RoadLOUISIANA22024
AtchafalayaLOUISIANA22024
Baton RougeLOUISIANA22023
DundeeMISSISSIPPI22010
Delta N.F.MISSISSIPPI22016
HughesARKANSAS12010
South BendARKANSAS12023
GillettARKANSAS12024
Morgan CityLOUISIANA11986
RoselandLOUISIANA11986
KeystoneLOUISIANA12003
MayflowerLOUISIANA12024
GibsonLOUISIANA12015

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