BirdAnalyst
Species · South Dakota · BBS 2026 Release · 1966–2025

Blue Jay Population Trend in South Dakota

All statesForest birds

Blue Jay in South Dakota has fallen sharply: down 61% on the route-weighted index since 1969.

-61%Since 1969TrendPercent 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 →
50Routes 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 South DakotaNotable 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 South Dakota: down 61% on the route-weighted index since 1969.

Blue Jay Population Forecast in South Dakota

If the recent trend holds, Blue Jay in South Dakota is projected to fall about 59% by 2030 — from 0.61 in 2025 to a central estimate of 0.25 (95% range 0.00–0.95). A 5-year backtest shows a typical error of ±66.4%, with 80% of held-out values landing inside the 95% band.

-59%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 →
0.25Projected 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 →
0.00–0.9595% 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 →
±66.4%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 South Dakota is projected to fall about 59% by 2030 — from 0.61 in 2025 to a central estimate of 0.25 (95% range 0.00–0.95). A 5-year backtest shows a typical error of ±66.4%, with 80% 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 →
20260.330.001.0
20270.310.001.0
20280.290.000.99
20290.270.000.97
20300.250.000.95

Blue Jay Survey Routes in South Dakota

Routes recording Blue Jay in South Dakota.
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 →
Chamberlain620111967
Roswell620111967
Gorman620071980
White River620131994
Lane519991967
Tripp420241967
Volga420251967
Crow Creek420231967
Wilmot420251967
Promise420131971
Custer320251967
Lennox220251967
Howard220251970
Geddes220231967
Winner220231968
Reva219931992
Hayes220062003
Englewood220181999
Elk Mountain220042002
French Creek219971997
White Lake119951968
Rosebud119881967
Rockyford120211968
Raymond120151968
Broadland120071967

Blue Jay Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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