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Species · Maryland · BBS 2025 Release · 1966–2024

Hairy Woodpecker Population Trend in Maryland

All statesForest birds

Hairy Woodpecker in Maryland has surged: up 328% on the route-weighted index since 1968.

+328%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 →
74Routes 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 Hairy Woodpecker 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 →

Hairy Woodpecker has surged in Maryland: up 328% on the route-weighted index since 1968.

Hairy Woodpecker Population Forecast in Maryland

If the recent trend holds, Hairy Woodpecker in Maryland is projected to rise about 20% by 2029 — from 1.1 in 2024 to a central estimate of 1.3 (95% range 0.92–1.6). A 5-year backtest shows a typical error of ±21.2%, with 80% of held-out values landing inside the 95% band.

+20%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 →
1.3Projected 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 →
0.92–1.695% 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 →
±21.2%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, Hairy Woodpecker in Maryland is projected to rise about 20% by 2029 — from 1.1 in 2024 to a central estimate of 1.3 (95% range 0.92–1.6). A 5-year backtest shows a typical error of ±21.2%, 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 →
20251.20.861.6
20261.20.881.6
20271.30.891.6
20281.30.911.6
20291.30.921.6

Hairy Woodpecker Survey Routes in Maryland

Routes recording Hairy Woodpecker 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 →
Madonna520222009
Piney Grove420241995
Berlin420241981
Island Creek420241991
Emmitsburg320241970
Beltsville320101972
Millington320241966
Finzel320241995
Green Ridge320231995
Mt Nebo219911972
Randallstown220121966
Walnut220162000
Tall Timbers220131966
La Plata220091966
Madison220241971
Fruitland219951968
Mardela220111984
Cokesbury220241966
Newark220231967
Jennings220241995
Steyer220241996
St. George'S Island220162016
Accident 2220242018
Earlton220242014
Pr Frederick220231992

Hairy Woodpecker Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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