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

Eastern Bluebird Population Trend in Maryland

All statesForest birds

Eastern Bluebird in Maryland has surged: up 742% on the route-weighted index since 1968.

+742%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 →
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 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 742% 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 fall about 19% by 2029 — from 12 in 2024 to a central estimate of 9.9 (95% range 7.2–13). A 5-year backtest shows a typical error of ±25%, with 60% of held-out values landing inside the 95% band.

-19%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 →
9.9Projected 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 →
7.2–1395% 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 →
±25%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 fall about 19% by 2029 — from 12 in 2024 to a central estimate of 9.9 (95% range 7.2–13). A 5-year backtest shows a typical error of ±25%, with 60% 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 →
20259.36.612
20269.46.712
20279.66.912
20289.87.112
20299.97.213

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 →
Cokesbury4320241972
Island Creek3320241991
Walnut3220242000
Olney2820241968
Madonna2820222009
Emmitsburg2720241966
Tall Timbers2720141967
Ijamsville2720241986
Earlton2720242014
Forest Grove2220232011
Nottingham2220242005
La Plata1920091966
Pr Frederick1820241991
Williamsport1720241967
Honga1620241970
Davidsnville1520241982
Smithsburg1420141967
Pomfret1420241967
Millington1420241972
Eklo1320181968
Potomac Park1220241970
Pomonkey1220241966
St. George'S Island1220172016
Elkton1120241987
Easton1120211973

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 2026-05-22.