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

Tricolored Heron In Mississippi Alluvial Valley

All regionsMississippi Alluvial ValleyWetland birds

Tricolored Heron in Mississippi Alluvial Valley has surged: up 146% on the route-weighted index since 1974.

+146%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 →
20Routes 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 →
45YearsYears 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 →

Tricolored Heron has surged in Mississippi Alluvial Valley: up 146% on the route-weighted index since 1974.

Forecast

If the recent trend holds, Tricolored Heron in Mississippi Alluvial Valley is projected to fall about 14% by 2029 — from 0.55 in 2024 to a central estimate of 0.47 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±287.4%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.47Projected 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 →
0.00–1.495% 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 →
±287.4%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, Tricolored Heron in Mississippi Alluvial Valley is projected to fall about 14% by 2029 — from 0.55 in 2024 to a central estimate of 0.47 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±287.4%, 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 →
20250.480.001.4
20260.480.001.4
20270.470.001.4
20280.470.001.4
20290.470.001.4

Routes In Mississippi Alluvial Valley

Routes recording Tricolored Heron 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 →
Morgan CityLOUISIANA131986
RoselandLOUISIANA92003
RamahLOUISIANA92024
KraemerLOUISIANA42024
ShawLOUISIANA32024
GibsonLOUISIANA32014
Morgan CityLOUISIANA32012
AtchafalayaLOUISIANA32019
CarlisleLOUISIANA21988
FreetownLOUISIANA22009
BelairLOUISIANA22023
KeystoneLOUISIANA12013
MayflowerLOUISIANA12024
LaroseLOUISIANA11990
FrogmoreLOUISIANA12023
BerwickLOUISIANA12016
Rayville 2LOUISIANA12013
Port AllenLOUISIANA12013
River RoadLOUISIANA12024
Baton RougeLOUISIANA12013

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