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

Woodhouse's Scrub-Jay Population Trend in Colorado

All statesGeneralists

Woodhouse's Scrub-Jay in Colorado has surged: up 110% on the route-weighted index since 1970.

+110%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 →
68Routes 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 Woodhouse's Scrub-Jay Trends in ColoradoNotable 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 →

Woodhouse's Scrub-Jay has surged in Colorado: up 110% on the route-weighted index since 1970.

Woodhouse's Scrub-Jay Population Forecast in Colorado

If the recent trend holds, Woodhouse's Scrub-Jay in Colorado is projected to rise about 10% by 2029 — from 0.79 in 2024 to a central estimate of 0.88 (95% range 0.27–1.5). A 5-year backtest shows a typical error of ±15.6%, with 100% of held-out values landing inside the 95% band.

+10%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 →
0.88Projected 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 →
0.27–1.595% 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 →
±15.6%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, Woodhouse's Scrub-Jay in Colorado is projected to rise about 10% by 2029 — from 0.79 in 2024 to a central estimate of 0.88 (95% range 0.27–1.5). A 5-year backtest shows a typical error of ±15.6%, 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 →
20250.850.241.4
20260.850.251.5
20270.860.261.5
20280.870.271.5
20290.880.271.5

Woodhouse's Scrub-Jay Survey Routes in Colorado

Routes recording Woodhouse's Scrub-Jay in Colorado.
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 →
Browns Park6320062006
Mesaverde Np1620241996
Walsenburg1620241994
Ludlow1320161998
Cortez 21020172010
Animas920041996
Angora820241998
Delta720211974
Cokedale520241995
Animas 2420182005
Lay420232022
Baxter Pass420241995
Buffalo Park420232023
De Beque420222021
Paonia420241993
Nucla420241999
Blackhead Pk420211996
Douglas Pass320241982
Rosevale320242010
Dinosaur320231995
Rifle Falls320211998
Gardner320221998
Maybell220241973
Dolores219871969
Pagosa Spgs219781968

Woodhouse's Scrub-Jay Population Trend in Other States

arizonacaliforniaidahonevadanew-mexicotexasutahwyoming

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