BirdAnalyst
Species · BCR 37 · BBS 2026 Release · 1966–2025

Great-tailed Grackle In Gulf Coastal Prairie

All regionsGulf Coastal PrairieWetland birds

Great-tailed Grackle in Gulf Coastal Prairie has fallen sharply: down 51% on the route-weighted index since 1969.

-51%Since 1969TrendPercent 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 →
44Routes 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 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 →

Great-tailed Grackle has fallen sharply in Gulf Coastal Prairie: down 51% on the route-weighted index since 1969.

Great-tailed Grackle In Gulf Coastal Prairie Population Forecast

If the recent trend holds, Great-tailed Grackle in Gulf Coastal Prairie is projected to fall about 70% by 2030 — from 55 in 2025 to a central estimate of 16 (95% range 0.00–114). A 5-year backtest shows a typical error of ±57.8%, with 100% of held-out values landing inside the 95% band.

-70%Change by 2030TrendPercent 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 →
16Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–11495% 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 →
±57.8%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, Great-tailed Grackle in Gulf Coastal Prairie is projected to fall about 70% by 2030 — from 55 in 2025 to a central estimate of 16 (95% range 0.00–114). A 5-year backtest shows a typical error of ±57.8%, with 100% of held-out values landing inside the 95% band.19672030
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 →
2026240.00122
2027220.00120
2028200.00118
2029180.00116
2030160.00114

Routes In Gulf Coastal Prairie

Routes recording Great-tailed Grackle in Gulf Coastal Prairie.
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 →
PetronilaTEXAS2552025
Lag AtascosaTEXAS2312025
L. Atascosa NwrTEXAS1652025
Gran ChenierLOUISIANA1481976
Bayside 3TEXAS1482025
BaysideTEXAS1272010
Bayside 2TEXAS1192004
CreoleLOUISIANA941987
StowellTEXAS862025
Forked Island 2LOUISIANA812011
Loyola Beach 2TEXAS672025
IndianolaTEXAS612024
Ltl Chenier 2LOUISIANA602011
Oyster LakeTEXAS602025
Loyola BeachTEXAS422009
ChinquapinTEXAS342025
Ltl ChenierLOUISIANA312025
WinnieTEXAS292025
DanburyTEXAS292025
Hackberry 2LOUISIANA242025
GlencoeLOUISIANA232012
Moon Lake 2TEXAS142025
Goliad PrairieTEXAS132016
San PedroTEXAS92025
MamouLOUISIANA81982

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.