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

Ruby-throated Hummingbird Population Trend in Connecticut

All statesGeneralists

Ruby-throated Hummingbird in Connecticut has surged: up 126% on the route-weighted index since 1973.

+126%Since 1973TrendPercent 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ruby-throated Hummingbird 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 →

Ruby-throated Hummingbird has surged in Connecticut: up 126% on the route-weighted index since 1973.

Ruby-throated Hummingbird Population Forecast in Connecticut

If the recent trend holds, Ruby-throated Hummingbird in Connecticut is projected to rise about 110% by 2029 — from 0.33 in 2024 to a central estimate of 0.70 (95% range 0.17–1.2). A 5-year backtest shows a typical error of ±104.9%, with 100% of held-out values landing inside the 95% band.

+110%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 →
0.70Projected 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 →
0.17–1.295% 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 →
±104.9%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, Ruby-throated Hummingbird in Connecticut is projected to rise about 110% by 2029 — from 0.33 in 2024 to a central estimate of 0.70 (95% range 0.17–1.2). A 5-year backtest shows a typical error of ±104.9%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.650.131.2
20260.660.141.2
20270.680.151.2
20280.690.161.2
20290.700.171.2

Ruby-throated Hummingbird Survey Routes in Connecticut

Routes recording Ruby-throated Hummingbird 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 →
Willimantic220182000
Danbury220162006
Warren220101985
Long Hill220181979
Mid Haddam220231973
Mystic120221978
E Hartland119851985
Buckingham120131967
Uncasville120241990
Woodstock120051990
Westbrook120181994
No Woodbury120241998
Sherman120191987
Greenwich120181968
Southington119931987
New Hartford120231995
Woodstock 2120242016
Warren 2120212016
Granby120191988

Ruby-throated Hummingbird Population Trend in Other States

alabamaarkansasdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsin

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