Connecticut Warbler
Connecticut Warbler has declined: down 36% on the route-weighted index since 1969.
About the Connecticut Warbler
The Connecticut Warbler (Oporornis agilis) is a North American member of the Wood-Warblers (Parulidae). In this analysis it is grouped with the forest birds.
- Size
- 4.5–5.5 in long (11–14 cm) — a small, active 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 75 Breeding Bird Survey routes across 4 states, most concentrated in the Boreal Hardwood Transition.
- Family
- Parulidae · Forest birds
Notable Connecticut Warbler Trends
No notable trend signals for Connecticut Warbler. See the full index history below.
Connecticut Warbler Population Forecast
If the recent trend holds, Connecticut Warbler is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±232.3%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.01 | 0.00 | 0.02 |
| 2026 | 0.01 | 0.00 | 0.02 |
| 2027 | 0.01 | 0.00 | 0.02 |
| 2028 | 0.01 | 0.00 | 0.02 |
| 2029 | 0.01 | 0.00 | 0.02 |
Where the Connecticut Warbler Is Detected
BBS routes recording Connecticut Warbler, sized by most recent count.
Connecticut Warbler Population Trend by State
| Michigan | +23% | 1980 | 17 |
| Minnesota | -32% | 1970 | 31 |
| New York | insufficient data | n/a | 1 |
| Wisconsin | -37% | 1969 | 26 |
Connecticut Warbler Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Boreal Hardwood Transition | -25% | 1969 | 68 |
Connecticut Warbler Conservation Status
Our route-weighted index shows it down about 36% since 1969.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.