BirdAnalyst
Species · Indiana · BBS 2026 Release · 1966–2025

Blue Grosbeak Population Trend in Indiana

All statesForest birds

Blue Grosbeak in Indiana has surged: up 33× on the route-weighted index since 1973.

33×Since 1973TrendPercent 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 →
45Routes 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 →
52YearsYears 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 IndianaNotable 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 Indiana: up 33× on the route-weighted index since 1973.

Blue Grosbeak Population Forecast in Indiana

If the recent trend holds, Blue Grosbeak in Indiana is projected to fall about 13% by 2030 — from 2.9 in 2025 to a central estimate of 2.5 (95% range 1.8–3.3). A 5-year backtest shows a typical error of ±37.4%, with 0% of held-out values landing inside the 95% band.

-13%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 →
2.5Projected 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 →
1.8–3.395% 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 →
±37.4%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 Indiana is projected to fall about 13% by 2030 — from 2.9 in 2025 to a central estimate of 2.5 (95% range 1.8–3.3). A 5-year backtest shows a typical error of ±37.4%, with 0% of held-out values landing inside the 95% band.19712030
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 →
20262.31.63.1
20272.41.63.1
20282.41.73.2
20292.51.73.2
20302.51.83.3

Blue Grosbeak Survey Routes in Indiana

Routes recording Blue Grosbeak in Indiana.
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 →
Newberry2120251999
Celestine1720251979
Washington1120251988
Brazil1020252002
Indian Spgs1020251987
Cyprss820252000
Clear Spring720251987
New Phila720251984
Evansville720221985
Millersburg620241981
Witts Station620252024
Spencer520241975
Azalia520252021
Vevay420251984
Pimento320252003
Brookville320251997
Cumback320251982
New Brunswick320252025
Lagrange320242016
Wallace320242022
Georgia320252000
Knox220252023
Thorntown220252016
Jamestown220252018
Sexton220222022

Blue Grosbeak Population Trend in Other States

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

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