BirdAnalyst
Species · Virginia · BBS 2025 Release · 1966–2024

Boat-tailed Grackle Population Trend in Virginia

All statesGeneralists

Boat-tailed Grackle in Virginia has fallen sharply: down 64% on the route-weighted index since 1980.

-64%Since 1980TrendPercent 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 →
7Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Boat-tailed Grackle Trends in VirginiaNotable 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 Virginia: down 64% on the route-weighted index since 1980.

Boat-tailed Grackle Population Forecast in Virginia

If the recent trend holds, Boat-tailed Grackle in Virginia is projected to stay roughly flat through 2029, near 0.74 (95% range 0.00–6.9). A 5-year backtest shows a typical error of ±3765.8%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.74Projected 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 →
0.00–6.995% 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 →
±3765.8%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, Boat-tailed Grackle in Virginia is projected to stay roughly flat through 2029, near 0.74 (95% range 0.00–6.9). A 5-year backtest shows a typical error of ±3765.8%, 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 →
20250.820.006.9
20260.800.006.9
20270.780.006.9
20280.760.006.9
20290.740.006.9

Boat-tailed Grackle Survey Routes in Virginia

Routes recording Boat-tailed Grackle in Virginia.
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 →
Quinby6520121968
Pungo320131987
Cornland219831982
White Stone220171980
Chincoteag W120241992
Cape Charles120111993
Sharps120012001

Boat-tailed Grackle Population Trend in Other States

alabamadelawarefloridageorgialouisianamarylandmississippinew-jerseynew-yorknorth-carolinasouth-carolinatexas

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