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

Blue Grosbeak Population Trend in Indiana

All statesGeneralists

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 →
44Routes 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 →
51YearsYears 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 stay roughly flat through 2029, near 2.4 (95% range 1.7–3.1). A 5-year backtest shows a typical error of ±35.9%, with 0% of held-out values landing inside the 95% band.

-9%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 →
2.4Projected 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 →
1.7–3.195% 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 →
±35.9%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 stay roughly flat through 2029, near 2.4 (95% range 1.7–3.1). A 5-year backtest shows a typical error of ±35.9%, with 0% of held-out values landing inside the 95% band.19712029
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 →
20252.21.52.9
20262.31.63.0
20272.31.63.0
20282.41.73.1
20292.41.73.1

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 →
Cumback1620211982
Newberry1620241999
Brazil1220242002
Clear Spring1220241987
New Phila1120241984
Celestine1020241979
Washington820241988
Vevay820241984
Indian Spgs720241987
Evansville720221985
Millersburg620241981
Georgia620242000
Pimento520242003
Spencer520241975
Cyprss520242000
Brookville420241997
Cross Plains420242006
Fowler320222009
Thorntown320242016
Azalia320242021
Lagrange320242016
Wallace320242022
Witts Station320242024
Jamestown220242018
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 2026-05-22.