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

Blue Grosbeak Population Trend in Virginia

All statesGeneralists

Blue Grosbeak in Virginia has surged: up 104% on the route-weighted index since 1968.

+104%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 →
74Routes 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 Grosbeak 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 increasecomputed 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 →

Blue Grosbeak has surged in Virginia: up 104% on the route-weighted index since 1968.

Blue Grosbeak Population Forecast in Virginia

If the recent trend holds, Blue Grosbeak in Virginia is projected to fall about 19% by 2029 — from 6.6 in 2024 to a central estimate of 5.4 (95% range 3.2–7.6). A 5-year backtest shows a typical error of ±14.7%, with 100% of held-out values landing inside the 95% band.

-19%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 →
5.4Projected 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 →
3.2–7.695% 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 →
±14.7%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 Grosbeak in Virginia is projected to fall about 19% by 2029 — from 6.6 in 2024 to a central estimate of 5.4 (95% range 3.2–7.6). A 5-year backtest shows a typical error of ±14.7%, 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 →
20255.33.27.5
20265.43.27.5
20275.43.27.5
20285.43.27.6
20295.43.27.6

Blue Grosbeak Survey Routes in Virginia

Routes recording Blue Grosbeak 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 →
Quinby3620241966
Newville3120241988
Finchley2820211994
Newsoms2420241971
Chincoteag W2320241992
Brandon2320241992
Port Royal1820191977
Branchville1820241966
Waverly1619871967
Surry1620241977
Ringgold1620241976
Gladys1620241994
Hall1420231967
Church Road1420241966
Brodnax1420241973
Concord1320241967
Cape Charles1320181992
White Stone1220241967
Mannboro1120241967
Cornland1120141975
Appomattox1020241995
Gloucester1020241992
Irisburg920241976
Truhart920241996
Sharps820241967

Blue Grosbeak Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradodelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-carolinasouth-dakotatennesseetexasutahwest-virginiawyoming

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