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

Blue Jay Population Trend in Delaware

All statesGeneralists

Blue Jay in Delaware has held roughly steady: up 4% on the route-weighted index since 1968.

+4%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 →
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 Blue Jay 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 Blue Jay in Delaware. See the full index history below.

Blue Jay Population Forecast in Delaware

If the recent trend holds, Blue Jay in Delaware is projected to fall about 32% by 2029 — from 11 in 2024 to a central estimate of 7.8 (95% range 2.6–13). A 5-year backtest shows a typical error of ±19%, with 100% of held-out values landing inside the 95% band.

-32%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 →
7.8Projected 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 →
2.6–1395% 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 →
±19%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, Blue Jay in Delaware is projected to fall about 32% by 2029 — from 11 in 2024 to a central estimate of 7.8 (95% range 2.6–13). A 5-year backtest shows a typical error of ±19%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20258.12.913
20268.02.913
20278.02.813
20287.92.713
20297.82.613

Blue Jay Survey Routes in Delaware

Routes recording Blue Jay 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 →
Holleyville2720041966
Blackbird1820241994
Holleyville 21620242006
Milton 21420172017
Lowes Xrds1319911966
Dover1219871966
Wilmington1120141966
Frederica1120141966
Milton1120161966
Millsboro1120242017
Georgetown1120221992
Harrington820241966
Bethany Bch819901966
Frankford620121966
Pepperbox 2420242017
Mt Pleasant320191966
Pepperbox320161998

Blue Jay Population Trend in Other States

alabamaarkansascoloradoconnecticutfloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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