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

Northern House Wren Population Trend in Maryland

All statesForest birds

Northern House Wren in Maryland has edged up: up 20% on the route-weighted index since 1968.

+20%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 →
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 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 stay roughly flat through 2029, near 9.5 (95% range 7.6–11). A 5-year backtest shows a typical error of ±11.6%, with 80% of held-out values landing inside the 95% band.

+4%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 →
9.5Projected 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 →
7.6–1195% 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 →
±11.6%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 stay roughly flat through 2029, near 9.5 (95% range 7.6–11). A 5-year backtest shows a typical error of ±11.6%, 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 →
20259.47.511
20269.47.511
20279.57.511
20289.57.611
20299.57.611

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 →
Emmitsburg5220241966
Wheaton4220241990
Earlton3120242014
Eklo3020181966
Olney2720241966
Madonna2620222009
Williamsport2520241966
Jennings2520241995
Madison2120241966
Warfieldsbrg2020241966
Finzel2020241995
Randallstown1820131966
Ijamsville1720241986
Smithsburg1520141966
Fair Hill1519961992
Mt Nebo1319911969
Silver Spg1319891966
Walnut1320241999
Pleasant Val1220241966
Van Bibber1120131966
Norwood1020121966
Bachman Mill1020241966
Accident 21020242018
Wolfsville920241966
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 2026-05-22.