BirdAnalyst
Species · New Hampshire · BBS 2025 Release · 1966–2024

Carolina Wren Population Trend in New Hampshire

All statesForest birds

Carolina Wren in New Hampshire has surged: up 20× on the route-weighted index since 2003.

20×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 →
13Routes 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 →
21YearsYears 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 20× 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 42% by 2029 — from 1.8 in 2024 to a central estimate of 1.0 (95% range 0.27–1.8). A 5-year backtest shows a typical error of ±66.8%, with 20% of held-out values landing inside the 95% band.

-42%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 →
1.0Projected 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 →
0.27–1.895% 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 →
±66.8%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 42% by 2029 — from 1.8 in 2024 to a central estimate of 1.0 (95% range 0.27–1.8). A 5-year backtest shows a typical error of ±66.8%, with 20% of held-out values landing inside the 95% band.19922029
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 →
20250.870.111.6
20260.910.151.7
20270.950.191.7
20280.990.231.7
20291.00.271.8

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 →
East Kingston1120242011
Dover720242003
Strafford620242015
Fitzwilliam520242009
Peterborough420242013
Epsom420232008
Concord420242006
Canterbury220222022
Hopkinton120242022
Gilmantn I W120212021
Walpole120222021
Marlow120241992
Milan119921992

Carolina Wren Population Trend in Other States

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

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