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Species · Utah · BBS 2025 Release · 1966–2024

Virginia's Warbler Population Trend in Utah

All statesForest birds

Virginia's Warbler in Utah has collapsed: down 78% on the route-weighted index since 1988.

-78%Since 1988TrendPercent 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 →
40Routes 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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Virginia's Warbler Trends in UtahNotable 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 declinecomputed 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 →

Virginia's Warbler has collapsed in Utah: down 78% on the route-weighted index since 1988.

Virginia's Warbler Population Forecast in Utah

If the recent trend holds, Virginia's Warbler in Utah is projected to fall about 100% by 2029 — from 0.42 in 2024 to a central estimate of 0.00 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±109.1%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1.495% 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 →
±109.1%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, Virginia's Warbler in Utah is projected to fall about 100% by 2029 — from 0.42 in 2024 to a central estimate of 0.00 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±109.1%, 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 →
20250.040.001.4
20260.020.001.4
20270.000.001.4
20280.000.001.4
20290.000.001.4

Virginia's Warbler Survey Routes in Utah

Routes recording Virginia's Warbler in Utah.
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 →
Beck 2920181990
Book Ridge520242003
Saleratus Cr420001995
Beaver420241992
La Sal 3420242007
Main Canyon420242004
La Sal 2320062003
Bryce Canyon320241996
Crawford Mts320232023
Skyline Driv320152012
Alton320111997
Lost Cr. Res220151995
Navajo Lake220241987
Hite220071993
Fayette220211994
Gooseberry220241996
Shivwitz220111994
Ant Flat-Ogden Can220221994
Uintah Nf219941994
Fish Lake Nf220182018
Moquith Mtn220021987
Moon Lake 2120232013
Altonah120071968
Grizzly Rdge120222022
Oak City120231987

Virginia's Warbler Population Trend in Other States

arizonacaliforniacoloradoidahonevadanew-mexicosouth-dakotawyoming

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