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

Nashville Warbler Population Trend in Idaho

All statesForest birds

Nashville Warbler in Idaho has surged: up 183% on the route-weighted index since 1977.

+183%Since 1977TrendPercent 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 →
29Routes 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Nashville 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 →

Nashville Warbler has surged in Idaho: up 183% on the route-weighted index since 1977.

Nashville Warbler Population Forecast in Idaho

If the recent trend holds, Nashville Warbler in Idaho is projected to rise about 16% by 2029 — from 0.48 in 2024 to a central estimate of 0.56 (95% range 0.07–1.0). A 5-year backtest shows a typical error of ±20.3%, with 80% of held-out values landing inside the 95% band.

+16%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 →
0.56Projected 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 →
0.07–1.095% 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 →
±20.3%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, Nashville Warbler in Idaho is projected to rise about 16% by 2029 — from 0.48 in 2024 to a central estimate of 0.56 (95% range 0.07–1.0). A 5-year backtest shows a typical error of ±20.3%, with 80% of held-out values landing inside the 95% band.19722029
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 →
20250.540.051.0
20260.540.061.0
20270.550.061.0
20280.550.071.0
20290.560.071.0

Nashville Warbler Survey Routes in Idaho

Routes recording Nashville 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 →
Centerville1320191983
Naples820241972
Lolo Pass820191992
Sunbeam819941994
Salmon River420131991
Rochat Divde320231994
Challis320212019
Coolin320241987
Mivoden220231977
Nezperce220121993
Grangeville219951995
Golden220161997
Pasadena Val219911991
Avery120231990
Gifford120091989
N Fork Cda R120051995
Cape Horn120182018
Triangle120122008
Glenns Ferry119861986
Baldy Mountain120152015
Marble Creek120231988
Pierce119971995
Burgdorf120151989
Cobalt120242024
Crane Creek120052004

Nashville Warbler Population Trend in Other States

californiaconnecticutmainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-dakotaoregonpennsylvaniarhode-islandvermontvirginiawashingtonwest-virginiawisconsin

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