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

Boat-tailed Grackle In Mississippi Alluvial Valley

All regionsMississippi Alluvial ValleyGeneralists

Boat-tailed Grackle in Mississippi Alluvial Valley has fallen sharply: down 73% on the route-weighted index since 1976.

-73%Since 1976TrendPercent 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 →
13Routes 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 →
35YearsYears 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 declinecomputed 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 →

Boat-tailed Grackle has fallen sharply in Mississippi Alluvial Valley: down 73% on the route-weighted index since 1976.

Boat-tailed Grackle In Mississippi Alluvial Valley Population Forecast

If the recent trend holds, Boat-tailed Grackle in Mississippi Alluvial Valley is projected to rise about 69% by 2029 — from 0.33 in 2024 to a central estimate of 0.56 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±826.9%, with 100% of held-out values landing inside the 95% band.

+69%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 →
0.56Projected 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 →
0.00–1.795% 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 →
±826.9%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, Boat-tailed Grackle in Mississippi Alluvial Valley is projected to rise about 69% by 2029 — from 0.33 in 2024 to a central estimate of 0.56 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±826.9%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.560.001.7
20260.560.001.7
20270.560.001.7
20280.560.001.7
20290.560.001.7

Routes In Mississippi Alluvial Valley

Routes recording Boat-tailed Grackle 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 →
BerwickLOUISIANA392018
GibsonLOUISIANA262019
LaroseLOUISIANA141992
FreetownLOUISIANA71987
River RoadLOUISIANA72024
KeystoneLOUISIANA61992
CarlisleLOUISIANA51988
Morgan CityLOUISIANA31976
KraemerLOUISIANA22024
MayflowerLOUISIANA11971
RamahLOUISIANA12024
BelairLOUISIANA12024
Morgan CityLOUISIANA12013

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