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

Warbling Vireo Population Trend in Washington

All statesForest birds

Warbling Vireo in Washington has surged: up 106% on the route-weighted index since 1970.

+106%Since 1970TrendPercent 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 →
88Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Warbling Vireo Trends in WashingtonNotable 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 →

Warbling Vireo has surged in Washington: up 106% on the route-weighted index since 1970.

Warbling Vireo Population Forecast in Washington

If the recent trend holds, Warbling Vireo in Washington is projected to stay roughly flat through 2029, near 11 (95% range 8.0–15). A 5-year backtest shows a typical error of ±13.8%, with 80% of held-out values landing inside the 95% band.

-6%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 →
11Projected 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 →
8.0–1595% 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 →
±13.8%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, Warbling Vireo in Washington is projected to stay roughly flat through 2029, near 11 (95% range 8.0–15). A 5-year backtest shows a typical error of ±13.8%, with 80% 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 →
2025117.414
2026117.614
2027117.715
2028117.915
2029118.015

Warbling Vireo Survey Routes in Washington

Routes recording Warbling Vireo in Washington.
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 →
Cougar8820231968
Montesand5720241987
Blewett Pass5620241995
Newhalem3720241968
Kamilche3620241968
Kendall3420241981
Spring Lake3020241985
Pe Ell2920231993
Rimrock2720241968
Cedar Falls2720141995
E. Mt. Adams2620241995
Mendota 32420242005
L. Wenatchee2120241993
Raymond 22120242022
Greenwater2020242015
Omak Creek1920241996
Twin Lakes1820241983
Ronald1820241973
Hurricane Rg1820241992
Ozette1720241971
Cusick1720241982
Ilwaco1720241976
Raymond1620211993
White Chuck1520241992
Mazama1520221993

Warbling Vireo Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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