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

Blue Jay Population Trend in Iowa

All statesGeneralists

Blue Jay in Iowa has declined: down 43% on the route-weighted index since 1969.

-43%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 →
39Routes 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 →
57YearsYears 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 IowaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Blue Jay in Iowa. See the full index history below.

Blue Jay Population Forecast in Iowa

If the recent trend holds, Blue Jay in Iowa is projected to fall about 27% by 2029 — from 5.0 in 2024 to a central estimate of 3.7 (95% range 1.4–6.0). A 5-year backtest shows a typical error of ±16.5%, with 100% of held-out values landing inside the 95% band.

-27%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 →
3.7Projected 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 →
1.4–6.095% 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 →
±16.5%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 Iowa is projected to fall about 27% by 2029 — from 5.0 in 2024 to a central estimate of 3.7 (95% range 1.4–6.0). A 5-year backtest shows a typical error of ±16.5%, 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 →
20253.91.66.2
20263.81.56.2
20273.81.56.1
20283.71.46.0
20293.71.46.0

Blue Jay Survey Routes in Iowa

Routes recording Blue Jay in Iowa.
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 →
Red Rock1720241968
Hudson1320221967
Mt Hamill1220241967
Bedford1220181968
Davis Corner1020241968
Festina920241968
Burchinal820241995
Mccallsburg820241996
College Spgs720041967
Wales720181967
Alice719991967
Cedar Valley619971967
Washington620241967
Zearing619951967
West Liberty520241968
Panther520241967
Neola520161968
Washta520141967
Sioux City520241968
College Spgs 2520232005
Williamsburg420231967
Exline320241974
Melrose320241974
Brooklyn320211967
Maquoketa320241967

Blue Jay Population Trend in Other States

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

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