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Species · Massachusetts · BBS 2025 Release · 1966–2024

Blue Jay Population Trend in Massachusetts

All statesGeneralists

Blue Jay in Massachusetts has fallen sharply: down 62% on the route-weighted index since 1968.

-62%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 →
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 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 62% 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 39% by 2029 — from 12 in 2024 to a central estimate of 7.2 (95% range 0.60–14). A 5-year backtest shows a typical error of ±39.8%, with 60% of held-out values landing inside the 95% band.

-39%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 →
7.2Projected 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 →
0.60–1495% 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 →
±39.8%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 39% by 2029 — from 12 in 2024 to a central estimate of 7.2 (95% range 0.60–14). A 5-year backtest shows a typical error of ±39.8%, with 60% 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 →
20258.72.115
20268.31.715
20277.91.315
20287.60.9814
20297.20.6014

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 →
E Pepperell3319941966
Belchertown2420241967
Princeton2219761969
Ware River2220221993
Chilmark2019831969
Mansfield2020241968
E Dennis1820211967
S Barre1820241968
Holden1720241977
Wellfleet 21620242016
Brockton1520191967
Prattville1420191966
Chesterfield1420241967
Maynard1320221967
Pittsfield1320161967
Gay Head1320241996
N Oxford1220241968
Wellfleet1020071966
Newburyport1020221967
N Orange1020241968
Hancock1020151997
Warren920091968
Monterey920242019
Cummington820141968
Cheshire719941969

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 2026-05-22.