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

Bobolink Population Trend in Connecticut

All statesGrassland birds

Bobolink in Connecticut has fallen sharply: down 72% on the route-weighted index since 1968.

-72%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 →
18Routes 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 Bobolink 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 declinecomputed 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 →

Bobolink has fallen sharply in Connecticut: down 72% on the route-weighted index since 1968.

Bobolink Population Forecast in Connecticut

If the recent trend holds, Bobolink in Connecticut is projected to rise about 80% by 2029 — from 0.56 in 2024 to a central estimate of 1.0 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±459.6%, with 80% of held-out values landing inside the 95% band.

+80%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 →
0.00–2.395% 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 →
±459.6%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, Bobolink in Connecticut is projected to rise about 80% by 2029 — from 0.56 in 2024 to a central estimate of 1.0 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±459.6%, with 80% 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 →
20251.10.002.3
20261.00.002.3
20271.00.002.3
20281.00.002.3
20291.00.002.3

Bobolink Survey Routes in Connecticut

Routes recording Bobolink 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 →
Woodstock 21020192019
Buckingham520141966
Sherman520191972
Uncasville320241977
Danbury319891969
Woodstock220071968
Westbrook219931972
Granby220191992
Mystic120211997
E Hartland119911966
Willimantic120011967
No Woodbury120241967
Warren120111972
Long Hill119741974
Mid Haddam120221973
Southington120071973
New Hartford119871972
Warren 2120242012

Bobolink Population Trend in Other States

californiacoloradoidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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