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

Bobolink Population Trend in Maryland

All statesGrassland birds

Bobolink in Maryland has surged: up 509% on the route-weighted index since 1970.

+509%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 →
56YearsYears 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 509% 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 64% by 2029 — from 0.57 in 2024 to a central estimate of 0.93 (95% range 0.47–1.4). A 5-year backtest shows a typical error of ±41.2%, with 100% of held-out values landing inside the 95% band.

+64%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 →
0.93Projected 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 →
0.47–1.495% 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 →
±41.2%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, Bobolink in Maryland is projected to rise about 64% by 2029 — from 0.57 in 2024 to a central estimate of 0.93 (95% range 0.47–1.4). A 5-year backtest shows a typical error of ±41.2%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.890.431.4
20260.900.441.4
20270.910.451.4
20280.920.461.4
20290.930.471.4

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 →
Floyd720241970
Emmitsburg720241977
Finzel620241995
Mt Nebo519911969
Accident520171992
Steyer420231996
Smithsburg320141978
Ijamsville320021987
Vindex220231968
Accident 2220242018
Jennings220241995
Elkton119781978
Williamsport120212021
Wolfsville120192005
Fair Hill119961993
Warfieldsbrg120161974

Bobolink Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.