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

Generalists In Iowa

All statesIowa

49 species in this guild. As a group they are -32%Guild trendA mean-index aggregate across the species in this group — the structural direction of the guild, with individual-species noise smoothed out.Full methodology → since 1969.

Guild SignalsNotable 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 generalists in Iowa. See the full index history below.

Generalists In Iowa Population Forecast

If the recent trend holds, Generalists in Iowa is projected to fall about 17% by 2029 — from 12 in 2024 to a central estimate of 9.8 (95% range 7.4–12). A 5-year backtest shows a typical error of ±6.5%, with 100% of held-out values landing inside the 95% band.

-17%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 →
9.8Projected 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 →
7.4–1295% 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 →
±6.5%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, Generalists in Iowa is projected to fall about 17% by 2029 — from 12 in 2024 to a central estimate of 9.8 (95% range 7.4–12). A 5-year backtest shows a typical error of ±6.5%, 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 →
2025108.013
2026107.813
2027107.713
202810.07.512
20299.87.412

Member Species In Iowa

Generalists species in Iowa.
TrendPercent 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 →
Loggerhead ShrikeLaniidae-86%
Black-billed CuckooCuculidae-75%
Yellow-billed CuckooCuculidae-71%
House SparrowPasseridae-67%
American GoldfinchFringillidae-60%
Swamp SparrowPasserellidae-59%
Rock PigeonColumbidae-58%
Brown ThrasherMimidae-57%
Field SparrowPasserellidae-52%
Blue JayCorvidae-43%
Yellow-headed BlackbirdIcteridae-43%
Common GrackleIcteridae-42%
Great Horned OwlStrigidae-41%
Eastern Screech-OwlStrigidae-38%
American CrowCorvidae-37%
Baltimore OrioleIcteridae-25%
Belted KingfisherAlcedinidae-25%
Great-tailed GrackleIcteridae-24%
European StarlingSturnidae-15%
Mourning DoveColumbidae-7%
Northern MockingbirdMimidae+3%
Song SparrowPasserellidae+5%
Red-winged BlackbirdIcteridae+10%
Rose-breasted GrosbeakCardinalidae+12%
Northern HarrierAccipitridae+14%
Scarlet TanagerCardinalidae+17%
Summer TanagerCardinalidae+21%
Barred OwlStrigidae+65%
Indigo BuntingCardinalidae+79%
Gray PartridgePhasianidae+83%
Brown-headed CowbirdIcteridae+85%
Northern CardinalCardinalidae+99%
Eastern TowheePasserellidae+103%
American KestrelFalconidae+110%
Gray CatbirdMimidae+183%
Orchard OrioleIcteridae+189%
Red-tailed HawkAccipitridae+200%
Cooper's HawkAccipitridae+244%
House FinchFringillidae+265%
Bald EagleAccipitridae+306%
Blue GrosbeakCardinalidae+344%
Yellow-breasted ChatIcteriidae+377%
Ruby-throated HummingbirdTrochilidae+391%
Cedar WaxwingBombycillidae+644%
Chipping SparrowPasserellidae+645%
Wild TurkeyPhasianidae13×
Turkey VultureCathartidae14×
Eurasian Tree SparrowPasseridae14×
Eurasian Collared-DoveColumbidae51×

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