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

Cerulean Warbler Population Trend in Indiana

All statesForest birds

Cerulean Warbler in Indiana has fallen sharply: down 55% on the route-weighted index since 1968.

-55%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 →
28Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cerulean Warbler 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 declinecomputed 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 →

Cerulean Warbler has fallen sharply in Indiana: down 55% on the route-weighted index since 1968.

Cerulean Warbler Population Forecast in Indiana

If the recent trend holds, Cerulean Warbler in Indiana is projected to rise about 37% by 2029 — from 0.13 in 2024 to a central estimate of 0.17 (95% range 0.00–0.38). A 5-year backtest shows a typical error of ±41.7%, with 100% of held-out values landing inside the 95% band.

+37%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 →
0.17Projected 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 →
0.00–0.3895% 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 →
±41.7%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, Cerulean Warbler in Indiana is projected to rise about 37% by 2029 — from 0.13 in 2024 to a central estimate of 0.17 (95% range 0.00–0.38). A 5-year backtest shows a typical error of ±41.7%, 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 →
20250.180.000.38
20260.180.000.38
20270.180.000.38
20280.170.000.38
20290.170.000.38

Cerulean Warbler Survey Routes in Indiana

Routes recording Cerulean Warbler 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 →
Hoosier320241990
Indiana Dune220221994
Middletown219901990
Cumback219961966
Vevay220011972
Knox119901990
Kewanna119831983
Packertown120041968
Ellis120091970
Monticello119851985
Galveston120101982
Wabash120092007
Pimento120212021
Belmont120241983
Spencer120131978
Azalia120021982
Shelbyville119861983
Brookville119741974
Indian Spgs120241986
Celestine120001980
Clear Spring120191981
New Phila120011984
Corydon120241966
Scottsburg119831982
Wallace120231999

Cerulean Warbler Population Trend in Other States

alabamaarkansasconnecticutgeorgiaillinoiskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniatennesseevermontvirginiawest-virginiawisconsin

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