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

Carolina Wren Population Trend in Delaware

All statesForest birds

Carolina Wren in Delaware has surged: up 13× on the route-weighted index since 1968.

13×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 →
17Routes 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 Carolina Wren Trends in DelawareNotable 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 Delaware: up 13× on the route-weighted index since 1968.

Carolina Wren Population Forecast in Delaware

If the recent trend holds, Carolina Wren in Delaware is projected to fall about 30% by 2029 — from 54 in 2024 to a central estimate of 38 (95% range 23–53). A 5-year backtest shows a typical error of ±40.7%, with 20% of held-out values landing inside the 95% band.

-30%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 →
38Projected 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 →
23–5395% 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 →
±40.7%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 Delaware is projected to fall about 30% by 2029 — from 54 in 2024 to a central estimate of 38 (95% range 23–53). A 5-year backtest shows a typical error of ±40.7%, with 20% 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 →
2025352051
2026362151
2027372152
2028372252
2029382353

Carolina Wren Survey Routes in Delaware

Routes recording Carolina Wren in Delaware.
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 →
Harrington8220241966
Pepperbox 27720242017
Holleyville 24720242006
Pepperbox4420161998
Milton 24320172017
Holleyville4120041966
Millsboro4120242017
Georgetown3320221992
Milton3120161966
Blackbird2520241994
Frankford2320121966
Lowes Xrds1819911966
Wilmington720141968
Mt Pleasant620191966
Dover519871966
Bethany Bch519901966
Frederica420141966

Carolina Wren Population Trend in Other States

alabamaarkansasconnecticutfloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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