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

Blue Grosbeak Population Trend in Delaware

All statesGeneralists

Blue Grosbeak in Delaware has surged: up 564% on the route-weighted index since 1968.

+564%Since 1968
17Routes In State
58Years

Notable Blue Grosbeak Trends in Delaware

long arc increasecomputed index

Blue Grosbeak has surged in Delaware: up 564% on the route-weighted index since 1968.

Blue Grosbeak Population Forecast in Delaware

If the recent trend holds, Blue Grosbeak in Delaware is projected to fall about 12% by 2029 — from 25 in 2024 to a central estimate of 22 (95% range 15–29). A 5-year backtest shows a typical error of ±21%, with 80% of held-out values landing inside the 95% band.

-12%Change by 2029
22Projected 2029 index
15–2995% range
±21%Backtest error
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 index95% low95% high
2025211328
2026211428
2027211429
2028221429
2029221529

Blue Grosbeak Survey Routes in Delaware

Routes recording Blue Grosbeak in Delaware.
Holleyville3720041966
Holleyville 23420242006
Milton 23220172017
Millsboro2720242017
Pepperbox2620161998
Pepperbox 22620242017
Georgetown2520221992
Blackbird2020241994
Harrington1720241969
Frankford1720121966
Milton1720161966
Frederica1620141966
Lowes Xrds619911966
Dover419871966
Mt Pleasant220191966
Wilmington220131966
Bethany Bch219891967

Blue Grosbeak Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradofloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvirginiawest-virginiawyoming

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