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Species · Maryland · BBS 2026 Release · 1966–2025

Brown-headed Nuthatch Population Trend in Maryland

All statesForest birds

Brown-headed Nuthatch in Maryland has surged: up 496% on the route-weighted index since 1968.

+496%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 →
12Routes 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 Brown-headed Nuthatch 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 →

Brown-headed Nuthatch has surged in Maryland: up 496% on the route-weighted index since 1968.

Brown-headed Nuthatch Population Forecast in Maryland

If the recent trend holds, Brown-headed Nuthatch in Maryland is projected to fall about 68% by 2030 — from 2.4 in 2025 to a central estimate of 0.78 (95% range 0.21–1.3). A 5-year backtest shows a typical error of ±50.2%, with 0% of held-out values landing inside the 95% band.

-68%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 →
0.78Projected 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 →
0.21–1.395% 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 →
±50.2%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, Brown-headed Nuthatch in Maryland is projected to fall about 68% by 2030 — from 2.4 in 2025 to a central estimate of 0.78 (95% range 0.21–1.3). A 5-year backtest shows a typical error of ±50.2%, with 0% 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 →
20260.720.161.3
20270.740.171.3
20280.750.191.3
20290.760.201.3
20300.780.211.3

Brown-headed Nuthatch Survey Routes in Maryland

Routes recording Brown-headed Nuthatch 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 →
Madison5620251966
Honga1920251966
Furnace Town820252015
Cokesbury720251968
Walnut520162010
Fruitland219661966
Melitota119891989
Newark120251974
Snow Hill119751975
Berlin120211982
Indiantown120051983
Island Creek120222022

Brown-headed Nuthatch Population Trend in Other States

alabamaarkansasdelawarefloridageorgialouisianamississippinorth-carolinaoklahomasouth-carolinatennesseetexasvirginia

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