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Species · Idaho · BBS 2025 Release · 1966–2024

MacGillivray's Warbler Population Trend in Idaho

All statesForest birds

MacGillivray's Warbler in Idaho has surged: up 96% on the route-weighted index since 1973.

+96%Since 1973TrendPercent 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 →
47Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable MacGillivray's Warbler Trends in IdahoNotable 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 increasecomputed 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 →

MacGillivray's Warbler has surged in Idaho: up 96% on the route-weighted index since 1973.

MacGillivray's Warbler Population Forecast in Idaho

If the recent trend holds, MacGillivray's Warbler in Idaho is projected to rise about 121% by 2029 — from 2.3 in 2024 to a central estimate of 5.0 (95% range 2.5–7.5). A 5-year backtest shows a typical error of ±88%, with 60% of held-out values landing inside the 95% band.

+121%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 →
5.0Projected 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 →
2.5–7.595% 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 →
±88%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, MacGillivray's Warbler in Idaho is projected to rise about 121% by 2029 — from 2.3 in 2024 to a central estimate of 5.0 (95% range 2.5–7.5). A 5-year backtest shows a typical error of ±88%, with 60% 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 →
20254.82.37.3
20264.92.47.4
20274.92.47.4
20285.02.57.5
20295.02.57.5

MacGillivray's Warbler Survey Routes in Idaho

Routes recording MacGillivray's Warbler in Idaho.
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 →
Golden4720161987
Pierce2720071990
Lolo Pass2520191992
Deep Creek2219851985
Mivoden1920231977
Magic Mtn1820241987
Centerville1620191972
N Fork Cda R1520191993
Baldy Mountain1520162013
Nezperce Nf1419991992
Cabarton1420231985
Nezperce1220121968
Cascade1019841982
Challis1020241975
Rochat Divde1020231993
Marble Creek1020231988
Avery920231979
Coolin920241986
Almo620221990
Naples520241972
Featherville520241989
Cobalt420241989
Sunbeam420191994
Burgdorf320161988
Yellow Pine320161989

MacGillivray's Warbler Population Trend in Other States

alaskaarizonacaliforniacoloradomontananevadanew-mexicooregonsouth-dakotatexasutahwashingtonwyoming

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