BirdAnalyst
Species · BCR 24 · BBS 2025 Release · 1966–2024

Blue Grosbeak In Central Hardwoods

All regionsCentral HardwoodsGeneralists

Blue Grosbeak in Central Hardwoods has surged: up 268% on the route-weighted index since 1968.

+268%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 →
161Routes 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 Central Hardwoods: up 268% on the route-weighted index since 1968.

Blue Grosbeak In Central Hardwoods Population Forecast

If the recent trend holds, Blue Grosbeak in Central Hardwoods is projected to stay roughly flat through 2029, near 7.1 (95% range 6.0–8.1). A 5-year backtest shows a typical error of ±8.8%, with 100% of held-out values landing inside the 95% band.

+5%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 →
7.1Projected 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 →
6.0–8.195% 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 →
±8.8%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 Central Hardwoods is projected to stay roughly flat through 2029, near 7.1 (95% range 6.0–8.1). A 5-year backtest shows a typical error of ±8.8%, 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 →
20256.85.77.8
20266.85.87.9
20276.95.98.0
20287.06.08.0
20297.16.08.1

Routes In Central Hardwoods

Routes recording Blue Grosbeak in Central Hardwoods.
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 →
GlenTENNESSEE252024
Bays ForkKENTUCKY242019
West PlainsMISSOURI202024
KarnakILLINOIS192024
Wheeler DamALABAMA182023
Ravenden SpringsARKANSAS182015
WhitewaterMISSOURI182024
HegiraKENTUCKY172024
FarwellARKANSAS162018
BremenILLINOIS162024
CumbackINDIANA162021
NewberryINDIANA162024
ComptonARKANSAS152022
Beaverdam LkILLINOIS152023
Rueter 2MISSOURI152024
BrownvilleILLINOIS142024
RoyaltonILLINOIS142024
Iron BridgeKENTUCKY141998
Sulphur LickKENTUCKY142024
DemunbrunsKENTUCKY142021
DelwoodILLINOIS132024
JoyKENTUCKY132023
Hodgenville 2KENTUCKY132023
ApexKENTUCKY132024
PleasurevillKENTUCKY132024

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