BirdAnalyst
Species · BCR 30 · BBS 2026 Release · 1966–2025

Blue Grosbeak In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastForest birds

Blue Grosbeak in New England / Mid-Atlantic Coast has surged: up 228% on the route-weighted index since 1968.

+228%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 →
93Routes In RegionSurvey 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 SignalsNotable 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 New England / Mid-Atlantic Coast: up 228% on the route-weighted index since 1968.

Blue Grosbeak In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Blue Grosbeak in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2030, near 7.9 (95% range 6.5–9.3). A 5-year backtest shows a typical error of ±14%, with 80% of held-out values landing inside the 95% band.

+2%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 →
7.9Projected 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 →
6.5–9.395% 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%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 New England / Mid-Atlantic Coast is projected to stay roughly flat through 2030, near 7.9 (95% range 6.5–9.3). A 5-year backtest shows a typical error of ±14%, with 80% 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 →
20267.66.28.9
20277.66.39.0
20287.76.39.1
20297.86.49.2
20307.96.59.3

Routes In New England / Mid-Atlantic Coast

Routes recording Blue Grosbeak in New England / Mid-Atlantic Coast.
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 →
CokesburyMARYLAND552025
HarmonyMARYLAND432017
HolleyvilleDELAWARE372004
Pepperbox 2DELAWARE352025
Holleyville 2DELAWARE342024
MillsboroDELAWARE322025
QuinbyVIRGINIA292025
HongaMARYLAND282025
BlackbirdDELAWARE272025
Furnace TownMARYLAND272025
PepperboxDELAWARE262016
MardelaMARYLAND262019
GeorgetownDELAWARE252022
St. George'S IslandMARYLAND252017
Milton 2DELAWARE242025
Tall TimbersMARYLAND242014
WalnutMARYLAND232024
Chincoteag WVIRGINIA232024
HarringtonDELAWARE222025
La PlataMARYLAND212009
ViennaMARYLAND212025
NewarkMARYLAND212025
BerlinMARYLAND212025
Forest GroveMARYLAND202023
MadisonMARYLAND192025

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