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

Field Sparrow Population Trend in Maryland

All statesGeneralists

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 →
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 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 75% 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 2029 — from 4.5 in 2024 to a central estimate of 0.52 (95% range 0.00–4.2). A 5-year backtest shows a typical error of ±73.9%, with 80% of held-out values landing inside the 95% band.

-89%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 →
0.52Projected 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 →
0.00–4.295% 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 →
±73.9%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, Field Sparrow in Maryland is projected to fall about 89% by 2029 — from 4.5 in 2024 to a central estimate of 0.52 (95% range 0.00–4.2). A 5-year backtest shows a typical error of ±73.9%, with 80% 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 →
20251.50.005.2
20261.20.005.0
20271.000.004.7
20280.760.004.5
20290.520.004.2

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 →
Ijamsville1620241986
Emmitsburg1420241966
Pt Republic1419891966
Madonna1420222009
Potomac Park1320241970
Smithsburg1320141966
Warfieldsbrg1220241966
Green Ridge1120241995
Finzel1020241995
Davidsnville1020241982
Mt Nebo919911969
La Plata920091966
Bachman Mill820241966
Eklo820181966
Hughesville820241966
Snow Hill819761966
Cheltenham720041966
Piney Neck720241966
Newark720241966
Oldtown620241970
Olney620241966
Harmony620171966
Piney Grove620241995
Forest Grove620232011
Walnut620241999

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 2026-05-22.