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

Northern House Wren Population Trend in Maryland

All statesForest birds

Northern House Wren in Maryland has edged up: up 12% on the route-weighted index since 1968.

+12%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 →
75Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern House Wren 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 Northern House Wren in Maryland. See the full index history below.

Northern House Wren Population Forecast in Maryland

If the recent trend holds, Northern House Wren in Maryland is projected to rise about 19% by 2030 — from 8.0 in 2025 to a central estimate of 9.5 (95% range 7.5–11). A 5-year backtest shows a typical error of ±15.1%, with 80% of held-out values landing inside the 95% band.

+19%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 →
9.5Projected 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 →
7.5–1195% 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 →
±15.1%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, Northern House Wren in Maryland is projected to rise about 19% by 2030 — from 8.0 in 2025 to a central estimate of 9.5 (95% range 7.5–11). A 5-year backtest shows a typical error of ±15.1%, with 80% 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 →
20269.37.411
20279.47.411
20289.47.411
20299.47.511
20309.57.511

Northern House Wren Survey Routes in Maryland

Routes recording Northern House Wren 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 →
Wheaton4720251990
Emmitsburg4120251966
Madison3220251966
Earlton3120242014
Eklo3020181966
Madonna2620222009
Williamsport2520251966
Jennings2520251995
Randallstown1820131966
Ijamsville1820251986
Pleasant Val1620251966
Smithsburg1520141966
Fair Hill1519961992
Mt Nebo1319911969
Silver Spg1319891966
Olney1320251966
Walnut1320241999
Van Bibber1120131966
Finzel1120251995
Floyd1020251966
Norwood1020121966
Warfieldsbrg1020251966
Bachman Mill1020251966
Honga1020251966
La Plata920091966

Northern House Wren Population Trend in Other States

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

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