Kentucky Warbler
Kentucky Warbler has declined: down 38% on the route-weighted index since 1968.
About the Kentucky Warbler
The Kentucky Warbler (Geothlypis formosa) 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 1,217 Breeding Bird Survey routes across 26 states, most concentrated in the Appalachian Mountains.
- Family
- Parulidae · Forest birds
Notable Kentucky Warbler Trends
No notable trend signals for Kentucky Warbler. See the full index history below.
Kentucky Warbler Population Forecast
If the recent trend holds, Kentucky Warbler is projected to stay roughly flat through 2029, near 0.37 (95% range 0.24–0.50). A 5-year backtest shows a typical error of ±9.7%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.38 | 0.25 | 0.51 |
| 2026 | 0.38 | 0.25 | 0.50 |
| 2027 | 0.38 | 0.25 | 0.50 |
| 2028 | 0.37 | 0.24 | 0.50 |
| 2029 | 0.37 | 0.24 | 0.50 |
Where the Kentucky Warbler Is Detected
BBS routes recording Kentucky Warbler, sized by most recent count.
Kentucky Warbler Population Trend by State
| Alabama | +24% | 1968 | 101 |
| Arkansas | -2% | 1969 | 52 |
| Delaware | -80% | 1968 | 15 |
| Florida | -53% | 1973 | 24 |
| Georgia | +7% | 1968 | 84 |
| Illinois | +224% | 1970 | 47 |
| Indiana | +100% | 1968 | 38 |
| Iowa | insufficient data | n/a | 2 |
| Kansas | +311% | 1977 | 13 |
| Kentucky | +22% | 1968 | 62 |
| Louisiana | +9% | 1969 | 68 |
| Maryland | -74% | 1968 | 74 |
| Mississippi | +194% | 1968 | 67 |
| Missouri | +580% | 1969 | 76 |
| New Jersey | +14% | 1970 | 19 |
| New York | insufficient data | n/a | 2 |
| North Carolina | -63% | 1968 | 72 |
| Ohio | +96% | 1968 | 46 |
| Oklahoma | +125% | 1969 | 27 |
| Pennsylvania | -90% | 1968 | 71 |
| South Carolina | +62% | 1968 | 36 |
| Tennessee | +47% | 1968 | 52 |
| Texas | -55% | 1969 | 35 |
| Virginia | -90% | 1968 | 73 |
| West Virginia | -80% | 1968 | 60 |
| Wisconsin | insufficient data | n/a | 1 |
Kentucky Warbler Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Lower Great Lakes / St. Lawrence Plain | -26% | 1971 | 8 |
| Oaks and Prairies | -0% | 1970 | 13 |
| Eastern Tallgrass Prairie | +386% | 1968 | 109 |
| Central Hardwoods | +63% | 1968 | 159 |
| West Gulf Coastal Plain / Ouachitas | -34% | 1969 | 109 |
| Mississippi Alluvial Valley | -8% | 1969 | 50 |
| Southeastern Coastal Plain | +90% | 1968 | 260 |
| Appalachian Mountains | -63% | 1968 | 291 |
| Piedmont | -34% | 1968 | 132 |
| New England / Mid-Atlantic Coast | -80% | 1968 | 78 |
Kentucky Warbler Conservation Status
Our route-weighted index shows it down about 38% 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.