Species · BBS 2025 Release · 1966–2024

Bell's Vireo

Bell's Vireo has surged: up 127% on the route-weighted index since 1968.

About the Bell's Vireo

The Bell's Vireo (Vireo bellii) is a North American member of the Vireos (Vireonidae). In this analysis it is grouped with the forest birds.

Size
4.5–6 in long (11–15 cm) — a small, deliberate songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 652 Breeding Bird Survey routes across 22 states, most concentrated in the Eastern Tallgrass Prairie.
Family
Vireonidae · Forest birds

Notable Bell's Vireo TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

Bell's Vireo has surged in surveyed states: up 127% on the route-weighted index since 1968.

Bell's Vireo Population Forecast

If the recent trend holds, Bell's Vireo is projected to stay roughly flat through 2029, near 0.43 (95% range 0.27–0.59). A 5-year backtest shows a typical error of ±24.5%, with 100% of held-out values landing inside the 95% band.

If the recent trend holds, Bell's Vireo is projected to stay roughly flat through 2029, near 0.43 (95% range 0.27–0.59). A 5-year backtest shows a typical error of ±24.5%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.410.250.57
20260.410.260.58
20270.420.260.58
20280.420.260.58
20290.430.270.59

Where the Bell's Vireo Is Detected

BBS routes recording Bell's Vireo, sized by most recent count.

Bell's Vireo Population Trend by State

Bell's Vireo population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona+35%197043
Arkansas-64%196929
California+725%197618
Coloradoinsufficient datan/a2
Illinois+9%196873
Indiana+255%197518
Iowa+186%196923
Kansas+189%196957
Kentucky-14%20116
Michiganinsufficient datan/a1
Minnesotainsufficient datan/a6
Missouri+140%196963
Nebraska+384%196963
Nevada-33%19964
New Mexico+816%199214
North Dakotainsufficient datan/a1
Ohioinsufficient datan/a1
Oklahoma-66%196953
South Dakota-44%196920
Texas+132%1969140
Utahinsufficient datan/a1
Wisconsin-39%197116

Bell's Vireo Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Bell's Vireo population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Prairie Potholes+39%196915
Southern Rockies / Colorado Plateau-75%19703
Badlands and Prairies-50%196918
Shortgrass Prairie-31%198321
Central Mixed Grass Prairie+201%1969107
Edwards Plateau+236%196919
Oaks and Prairies-50%196950
Eastern Tallgrass Prairie+74%1968169
Prairie Hardwood Transition-63%197126
Central Hardwoods+235%196955
West Gulf Coastal Plain / Ouachitas-88%196925
Mississippi Alluvial Valley-60%197212
Coastal California+481%197613
Sonoran and Mojave Deserts+58%197029
Sierra Madre Occidental-18%197020
Chihuahuan Desert+210%196940
Tamaulipan Brushlands-76%196923

Bell's Vireo Conservation Status

Our route-weighted index shows it up about 127% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.