Gray Vireo
Gray Vireo has surged: up 386% on the route-weighted index since 1970.
About the Gray Vireo
The Gray Vireo (Vireo vicinior) 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 137 Breeding Bird Survey routes across 7 states, most concentrated in the Southern Rockies / Colorado Plateau.
- Family
- Vireonidae · Forest birds
Notable Gray Vireo Trends
No notable trend signals for Gray Vireo. See the full index history below.
Gray Vireo Population Forecast
If the recent trend holds, Gray Vireo is projected to rise about 11% by 2029 — from 0.06 in 2024 to a central estimate of 0.07 (95% range 0.05–0.09). A 5-year backtest shows a typical error of ±25.1%, with 60% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.07 | 0.04 | 0.09 |
| 2026 | 0.07 | 0.04 | 0.09 |
| 2027 | 0.07 | 0.05 | 0.09 |
| 2028 | 0.07 | 0.05 | 0.09 |
| 2029 | 0.07 | 0.05 | 0.09 |
Where the Gray Vireo Is Detected
BBS routes recording Gray Vireo, sized by most recent count.
Gray Vireo Population Trend by State
| Arizona | +12% | 1970 | 24 |
| California | -83% | 1979 | 3 |
| Colorado | +374% | 1976 | 25 |
| Nevada | insufficient data | n/a | 4 |
| New Mexico | +206% | 1977 | 24 |
| Texas | +67% | 1990 | 12 |
| Utah | +13% | 1974 | 45 |
Gray Vireo Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Great Basin | +192% | 1998 | 10 |
| Southern Rockies / Colorado Plateau | +96% | 1970 | 85 |
| Sierra Madre Occidental | -11% | 1975 | 16 |
| Chihuahuan Desert | +148% | 1994 | 13 |
Gray Vireo Conservation Status
Our route-weighted index shows it up about 386% since 1970.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.