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

Grassland Birds In Idaho

All statesIdaho

9 species in this guild. As a group they are -48%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 1970.

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 →

guild collapsecomputed 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 →

Grassland birds as a group have declined in Idaho, down 48% since 1970.

Grassland Birds In Idaho Population Forecast

If the recent trend holds, Grassland birds in Idaho is projected to fall about 27% by 2029 — from 10 in 2024 to a central estimate of 7.5 (95% range 0.00–15). A 5-year backtest shows a typical error of ±29.9%, 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 →
7.5Projected 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 →
0.00–1595% 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 →
±29.9%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, Grassland birds in Idaho is projected to fall about 27% by 2029 — from 10 in 2024 to a central estimate of 7.5 (95% range 0.00–15). A 5-year backtest shows a typical error of ±29.9%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20258.00.4116
20267.90.2916
20277.80.1715
20287.70.0615
20297.50.0015

Member Species In Idaho

Grassland birds species in Idaho.
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 →
Lark BuntingPasserellidae-96%
Ring-necked PheasantPhasianidae-92%
Grasshopper SparrowPasserellidae-47%
Western MeadowlarkIcteridae-47%
Savannah SparrowPasserellidae-23%
BobolinkIcteridae+2%
Horned LarkAlaudidae+9%
Lark SparrowPasserellidae+23%
Vesper SparrowPasserellidae+323%

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