BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Canada Warbler

ParulidaeForest birdsCardellina canadensis

Canada Warbler has fallen sharply: down 60% on the route-weighted index since 1968.

-60%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 →
491RoutesSurvey 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 Canada Warbler

The Canada Warbler (Cardellina canadensis) 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 491 Breeding Bird Survey routes across 20 states, most concentrated in the Atlantic Northern Forest.
Family
Parulidae · Forest birds

Notable Canada 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 declinecomputed 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 →

Canada Warbler has fallen sharply in surveyed states: down 60% on the route-weighted index since 1968.

Canada Warbler Population Forecast

If the recent trend holds, Canada Warbler is projected to fall about 50% by 2029 — from 0.09 in 2024 to a central estimate of 0.04 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±43%, with 80% of held-out values landing inside the 95% band.

-50%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 →
0.04Projected 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 →
0.00–0.0995% 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 →
±43%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, Canada Warbler is projected to fall about 50% by 2029 — from 0.09 in 2024 to a central estimate of 0.04 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±43%, with 80% 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 →
20250.060.010.10
20260.050.000.10
20270.050.000.10
20280.050.000.10
20290.040.000.09

Where the Canada Warbler Is Detected

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

Canada Warbler Population Trend by State

Canada 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 →
Connecticut-85%196814
Georgiainsufficient datan/a1
Indianainsufficient datan/a1
Maine-85%196873
Maryland-49%19687
Massachusetts-72%196916
Michigan-5%196953
Minnesota+156%196932
New Hampshire-86%196826
New Jerseyinsufficient datan/a6
New York-62%196880
North Carolina+6%197613
Ohioinsufficient datan/a1
Pennsylvania+46%196860
Rhode Island-77%19694
Tennessee+135%19914
Vermont-80%196822
Virginia+266%197715
West Virginia12×197818
Wisconsin+14%196845

Canada Warbler Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Canada 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 →
Boreal Hardwood Transition+94%1968101
Lower Great Lakes / St. Lawrence Plain-77%196830
Atlantic Northern Forest-80%1968150
Prairie Hardwood Transition-65%197230
Appalachian Mountains+73%1968145
New England / Mid-Atlantic Coast-90%196834

Canada Warbler Conservation Status

Our route-weighted index shows it down about 60% 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.