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

Brown Creeper Population Trend in Connecticut

All statesForest birds

Brown Creeper in Connecticut has surged: up 98% on the route-weighted index since 1971.

+98%Since 1971TrendPercent 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 →
19Routes 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 →
45YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Brown Creeper Trends in ConnecticutNotable 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 →

Brown Creeper has surged in Connecticut: up 98% on the route-weighted index since 1971.

Brown Creeper Population Forecast in Connecticut

If the recent trend holds, Brown Creeper in Connecticut is projected to fall about 74% by 2030 — from 0.63 in 2025 to a central estimate of 0.16 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±55.5%, with 60% of held-out values landing inside the 95% band.

-74%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 →
0.16Projected 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 →
0.00–0.5095% 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 →
±55.5%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, Brown Creeper in Connecticut is projected to fall about 74% by 2030 — from 0.63 in 2025 to a central estimate of 0.16 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±55.5%, with 60% of held-out values landing inside the 95% band.19672030
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 →
20260.170.000.51
20270.170.000.50
20280.170.000.50
20290.160.000.50
20300.160.000.50

Brown Creeper Survey Routes in Connecticut

Routes recording Brown Creeper in Connecticut.
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 →
Sherman219921976
Mystic119891976
E Hartland119841984
Buckingham120012001
Uncasville120252014
Woodstock119901971
Westbrook119921986
Willimantic120051974
No Woodbury120251967
Greenwich119841968
Danbury119721968
Warren120111974
Long Hill120171975
Mid Haddam120251975
New Hartford119871977
New Hartford120241995
Woodstock 2120242016
Warren 2120252013
Granby120251989

Brown Creeper Population Trend in Other States

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