BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Blue Grosbeak In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastGeneralists

Blue Grosbeak in New England / Mid-Atlantic Coast has surged: up 213% on the route-weighted index since 1968.

+213%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 →
92Routes 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 →
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 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 213% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Blue Grosbeak in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 7.8 (95% range 6.4–9.2). A 5-year backtest shows a typical error of ±17.7%, with 80% of held-out values landing inside the 95% band.

+8%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 →
6.4–9.295% 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 →
±17.7%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 New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 7.8 (95% range 6.4–9.2). A 5-year backtest shows a typical error of ±17.7%, with 80% 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 →
20257.46.08.8
20267.56.18.9
20277.66.29.0
20287.76.39.1
20297.86.49.2

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 →
CokesburyMARYLAND452024
HarmonyMARYLAND432017
HolleyvilleDELAWARE372004
QuinbyVIRGINIA362024
Holleyville 2DELAWARE342024
Milton 2DELAWARE322017
EastonMARYLAND302021
MillsboroDELAWARE272024
PepperboxDELAWARE262016
Pepperbox 2DELAWARE262024
MardelaMARYLAND262019
GeorgetownDELAWARE252022
St. George'S IslandMARYLAND252017
Tall TimbersMARYLAND242014
WalnutMARYLAND232024
BrandonVIRGINIA232024
Chincoteag WVIRGINIA232024
La PlataMARYLAND212009
NewarkMARYLAND212024
BlackbirdDELAWARE202024
Forest GroveMARYLAND202023
BerlinMARYLAND202024
MillingtonMARYLAND192024
HongaMARYLAND182024
ViennaMARYLAND182024

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