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Species · Massachusetts · BBS 2026 Release · 1966–2025

Blue Jay Population Trend in Massachusetts

All statesForest birds

Blue Jay in Massachusetts has fallen sharply: down 59% on the route-weighted index since 1968.

-59%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 →
32Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Blue Jay Trends in MassachusettsNotable 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 →

Blue Jay has fallen sharply in Massachusetts: down 59% on the route-weighted index since 1968.

Blue Jay Population Forecast in Massachusetts

If the recent trend holds, Blue Jay in Massachusetts is projected to fall about 51% by 2030 — from 15 in 2025 to a central estimate of 7.3 (95% range 0.59–14). A 5-year backtest shows a typical error of ±42.5%, with 40% of held-out values landing inside the 95% band.

-51%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 →
7.3Projected 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 →
0.59–1495% 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 →
±42.5%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, Blue Jay in Massachusetts is projected to fall about 51% by 2030 — from 15 in 2025 to a central estimate of 7.3 (95% range 0.59–14). A 5-year backtest shows a typical error of ±42.5%, with 40% of held-out values landing inside the 95% band.19662030
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 →
20268.72.015
20278.41.715
20288.01.315
20297.70.9514
20307.30.5914

Blue Jay Survey Routes in Massachusetts

Routes recording Blue Jay in Massachusetts.
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 →
Belchertown4320251967
E Pepperell3319941966
Wellfleet 23220252016
Princeton2219761969
Ware River2220221993
Chilmark2019831969
Mansfield1920251968
E Dennis1820211967
Maynard1820251967
Littleton1820251967
Brockton1520191967
N Orange1520251968
Prattville1420191966
S Barre1420251968
Cummington 21420252015
Pittsfield1320161967
Warren 21220252010
Wellfleet1020071966
Newburyport1020221967
Hancock1020151997
Marion920251966
Warren920091968
Gay Head920251996
N Oxford820251968
Cummington820141968

Blue Jay Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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