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Species · Maryland · BBS 2026 Release · 1966–2025

Eastern Bluebird Population Trend in Maryland

All statesForest birds

Eastern Bluebird in Maryland has surged: up 697% on the route-weighted index since 1968.

+697%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 →
76Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Eastern Bluebird Trends in MarylandNotable 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 →

Eastern Bluebird has surged in Maryland: up 697% on the route-weighted index since 1968.

Eastern Bluebird Population Forecast in Maryland

If the recent trend holds, Eastern Bluebird in Maryland is projected to stay roughly flat through 2030, near 10 (95% range 7.4–13). A 5-year backtest shows a typical error of ±24.8%, with 40% of held-out values landing inside the 95% band.

+3%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 →
10Projected 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 →
7.4–1395% 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 →
±24.8%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, Eastern Bluebird in Maryland is projected to stay roughly flat through 2030, near 10 (95% range 7.4–13). A 5-year backtest shows a typical error of ±24.8%, with 40% of held-out values landing inside the 95% band.19662030
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 →
20269.56.812
20279.67.012
20289.87.112
202910.07.313
2030107.413

Eastern Bluebird Survey Routes in Maryland

Routes recording Eastern Bluebird in Maryland.
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 →
Island Creek3920251991
Olney3720251968
Walnut3220242000
Madonna2820222009
Tall Timbers2720141967
Earlton2720242014
Ijamsville2620251986
Forest Grove2220232011
La Plata1920091966
Honga1720251970
Pr Frederick1720251991
Smithsburg1420141967
Emmitsburg1420251966
Pomfret1420241967
Eklo1320181968
Madison1320251973
Cokesbury1320251972
Nottingham1320252005
Williamsport1220251967
Wolfsville1220251966
Elkton1220251987
Jennings1220251995
St. George'S Island1220172016
Warfieldsbrg1020251966
Broomes Isl1019961966

Eastern Bluebird Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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