BirdAnalyst
Species · Delaware · BBS 2026 Release · 1966–2025

Common Grackle Population Trend in Delaware

All statesGeneralists

Common Grackle in Delaware has declined: down 44% on the route-weighted index since 1968.

-44%Since 1968TrendPercent 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 →
17Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Grackle Trends in DelawareNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Common Grackle in Delaware. See the full index history below.

Common Grackle Population Forecast in Delaware

If the recent trend holds, Common Grackle in Delaware is projected to stay roughly flat through 2030, near 116 (95% range 9.1–224). A 5-year backtest shows a typical error of ±98.6%, with 100% of held-out values landing inside the 95% band.

+8%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 →
116Projected 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 →
9.1–22495% 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 →
±98.6%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, Common Grackle in Delaware is projected to stay roughly flat through 2030, near 116 (95% range 9.1–224). A 5-year backtest shows a typical error of ±98.6%, with 100% of held-out values landing inside the 95% band.19662030
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 →
202612315230
202712114228
202812012227
202911811225
20301169.1224

Common Grackle Survey Routes in Delaware

Routes recording Common Grackle in Delaware.
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 →
Lowes Xrds23819911966
Milton 221820252017
Holleyville20420041966
Dover20019871966
Frankford16420121966
Milton12420161966
Pepperbox 211520252017
Harrington11320251966
Frederica9720251966
Bethany Bch6719901966
Holleyville 26520242006
Blackbird6320251994
Pepperbox5820161998
Mt Pleasant3920191966
Millsboro3820252017
Wilmington3320141966
Georgetown2920221992

Common Grackle Population Trend in Other States

alabamaarkansascoloradoconnecticutfloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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