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

Bobolink Population Trend in Maryland

All statesGrassland birds

Bobolink in Maryland has surged: up 359% on the route-weighted index since 1970.

+359%Since 1970TrendPercent 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 →
16Routes 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 Bobolink 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 →

Bobolink has surged in Maryland: up 359% on the route-weighted index since 1970.

Bobolink Population Forecast in Maryland

If the recent trend holds, Bobolink in Maryland is projected to rise about 163% by 2030 — from 0.34 in 2025 to a central estimate of 0.90 (95% range 0.42–1.4). A 5-year backtest shows a typical error of ±58.5%, with 80% of held-out values landing inside the 95% band.

+163%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 →
0.90Projected 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 →
0.42–1.495% 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 →
±58.5%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, Bobolink in Maryland is projected to rise about 163% by 2030 — from 0.34 in 2025 to a central estimate of 0.90 (95% range 0.42–1.4). A 5-year backtest shows a typical error of ±58.5%, with 80% of held-out values landing inside the 95% band.19682030
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 →
20260.860.381.3
20270.870.391.4
20280.880.401.4
20290.890.411.4
20300.900.421.4

Bobolink Survey Routes in Maryland

Routes recording Bobolink 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 →
Emmitsburg620251977
Mt Nebo519911969
Accident520171992
Floyd420251970
Steyer420231996
Smithsburg320141978
Ijamsville320021987
Vindex220231968
Accident 2220242018
Jennings220251995
Elkton119781978
Williamsport120212021
Wolfsville120192005
Fair Hill119961993
Warfieldsbrg120161974
Finzel120251995

Bobolink Population Trend in Other States

californiacoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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