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

Field Sparrow Population Trend in Maryland

All statesForest birds

Field Sparrow in Maryland has collapsed: down 76% on the route-weighted index since 1968.

-76%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 Field Sparrow 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 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 →

Field Sparrow has collapsed in Maryland: down 76% on the route-weighted index since 1968.

Field Sparrow Population Forecast in Maryland

If the recent trend holds, Field Sparrow in Maryland is projected to fall about 89% by 2030 — from 4.4 in 2025 to a central estimate of 0.51 (95% range 0.00–4.3). A 5-year backtest shows a typical error of ±74.2%, with 60% of held-out values landing inside the 95% band.

-89%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 →
0.51Projected 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 →
0.00–4.395% 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 →
±74.2%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, Field Sparrow in Maryland is projected to fall about 89% by 2030 — from 4.4 in 2025 to a central estimate of 0.51 (95% range 0.00–4.3). A 5-year backtest shows a typical error of ±74.2%, with 60% 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 →
20261.40.005.2
20271.20.005.0
20280.980.004.7
20290.740.004.5
20300.510.004.3

Field Sparrow Survey Routes in Maryland

Routes recording Field Sparrow 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 →
Emmitsburg1820251966
Finzel1720251995
Green Ridge1720251995
Pt Republic1419891966
Jennings1420251995
Madonna1420222009
Williamsport1320251966
Smithsburg1320141966
Hughesville1120251966
Mt Nebo919911969
La Plata920091966
Eklo820181966
Madison820251966
Snow Hill819761966
Cheltenham720041966
Potomac Park620251970
Olney620251966
Bachman Mill620251966
Harmony620171966
Forest Grove620232011
Walnut620241999
Ijamsville620251986
Sinepuxent519781966
Piney Grove520251995
Bald Friar519961992

Field Sparrow Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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