BirdAnalyst
Species · New Hampshire · BBS 2026 Release · 1966–2025

Carolina Wren Population Trend in New Hampshire

All statesForest birds

Carolina Wren in New Hampshire has surged: up 28× on the route-weighted index since 2003.

28×Since 2003TrendPercent 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 →
14Routes 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 →
22YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Carolina Wren Trends in New HampshireNotable 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 →

Carolina Wren has surged in New Hampshire: up 28× on the route-weighted index since 2003.

Carolina Wren Population Forecast in New Hampshire

If the recent trend holds, Carolina Wren in New Hampshire is projected to fall about 34% by 2030 — from 2.0 in 2025 to a central estimate of 1.3 (95% range 0.41–2.2). A 5-year backtest shows a typical error of ±77.1%, with 0% of held-out values landing inside the 95% band.

-34%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 →
1.3Projected 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 →
0.41–2.295% 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 →
±77.1%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, Carolina Wren in New Hampshire is projected to fall about 34% by 2030 — from 2.0 in 2025 to a central estimate of 1.3 (95% range 0.41–2.2). A 5-year backtest shows a typical error of ±77.1%, with 0% of held-out values landing inside the 95% band.19922030
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 →
20261.10.212.0
20271.10.262.0
20281.20.312.1
20291.20.362.1
20301.30.412.2

Carolina Wren Survey Routes in New Hampshire

Routes recording Carolina Wren in New Hampshire.
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 →
Dover1020252003
Epsom620252008
Fitzwilliam520252009
East Kingston520252011
Peterborough420252013
Concord420252006
Hopkinton320252022
Canterbury320252022
Walpole220252021
Strafford120252015
Gilmantn I W120212021
Wilmot120252025
Marlow120251992
Milan119921992

Carolina Wren Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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