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Species · Maryland · BBS 2026 Release · 1966–2025

Blue-headed Vireo Population Trend in Maryland

All statesForest birds

Blue-headed Vireo in Maryland has surged: up 14× on the route-weighted index since 1968.

14×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 →
11Routes 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 Blue-headed Vireo 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 →

No notable trend signals for Blue-headed Vireo in Maryland. See the full index history below.

Blue-headed Vireo Population Forecast in Maryland

If the recent trend holds, Blue-headed Vireo in Maryland is projected to rise about 82% by 2030 — from 0.34 in 2025 to a central estimate of 0.62 (95% range 0.39–0.85). A 5-year backtest shows a typical error of ±35%, with 40% of held-out values landing inside the 95% band.

+82%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 →
0.62Projected 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 →
0.39–0.8595% 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 →
±35%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, Blue-headed Vireo in Maryland is projected to rise about 82% by 2030 — from 0.34 in 2025 to a central estimate of 0.62 (95% range 0.39–0.85). A 5-year backtest shows a typical error of ±35%, with 40% 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 →
20260.580.340.81
20270.590.360.82
20280.600.370.83
20290.610.380.84
20300.620.390.85

Blue-headed Vireo Survey Routes in Maryland

Routes recording Blue-headed Vireo 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 →
Jennings1020251995
Vindex320241966
Steyer320241996
Accident220171993
Accident 2220242018
Finzel220251995
Floyd120241966
Mt Nebo119911969
Oldtown120251982
Green Ridge120231995
Piney Grove120212014

Blue-headed Vireo Population Trend in Other States

alabamaconnecticutgeorgiakentuckymainemassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandsouth-carolinatennesseevermontvirginiawest-virginiawisconsin

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