BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Nashville Warbler

ParulidaeForest birdsLeiothlypis ruficapilla

Nashville Warbler has surged: up 142% on the route-weighted index since 1968.

+142%Since 1968TrendPercent 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 →
726RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Nashville Warbler

The Nashville Warbler (Leiothlypis ruficapilla) 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 726 Breeding Bird Survey routes across 21 states, most concentrated in the Atlantic Northern Forest.
Family
Parulidae · Forest birds

Notable Nashville Warbler TrendsNotable 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 →

Nashville Warbler has surged in surveyed states: up 142% on the route-weighted index since 1968.

Nashville Warbler Population Forecast

If the recent trend holds, Nashville Warbler is projected to rise about 40% by 2029 — from 0.79 in 2024 to a central estimate of 1.1 (95% range 0.79–1.4). A 5-year backtest shows a typical error of ±27%, with 60% of held-out values landing inside the 95% band.

+40%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 →
1.1Projected 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 →
0.79–1.495% 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 →
±27%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, Nashville Warbler is projected to rise about 40% by 2029 — from 0.79 in 2024 to a central estimate of 1.1 (95% range 0.79–1.4). A 5-year backtest shows a typical error of ±27%, with 60% 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 →
20251.10.761.4
20261.10.771.4
20271.10.771.4
20281.10.781.4
20291.10.791.4

Where the Nashville Warbler Is Detected

BBS routes recording Nashville Warbler, sized by most recent count.

Nashville Warbler Population Trend by State

Nashville Warbler 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 →
California+435%1970107
Connecticutinsufficient datan/a7
Idaho+183%197729
Maine-66%196876
Marylandinsufficient datan/a1
Massachusetts-71%196822
Michigan+670%196867
Minnesota+105%196945
Montana+444%198123
New Hampshire-45%196825
New Jerseyinsufficient datan/a1
New York+7%196878
North Dakotainsufficient datan/a1
Oregon+351%197063
Pennsylvania-68%196940
Rhode Islandinsufficient datan/a1
Vermont-13%196824
Virginiainsufficient datan/a1
Washington+928%197054
West Virginiainsufficient datan/a3
Wisconsin+96%196858

Nashville Warbler Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Nashville Warbler 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 →
Northern Pacific Rainforest+65%197080
Great Basin+575%197163
Northern Rockies+290%197075
Prairie Potholes-54%19906
Boreal Hardwood Transition+187%1968124
Lower Great Lakes / St. Lawrence Plain+47%196936
Atlantic Northern Forest-37%1968152
Sierra Nevada+62%197335
Prairie Hardwood Transition-43%196841
Appalachian Mountains-88%196864
New England / Mid-Atlantic Coast-75%196826
Coastal California+67%197122

Nashville Warbler Conservation Status

Our route-weighted index shows it up about 142% 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.