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Species · Maryland · BBS 2025 Release · 1966–2024

Canada Warbler Population Trend in Maryland

All statesForest birds

Canada Warbler in Maryland has declined: down 49% on the route-weighted index since 1968.

-49%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 →
7Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Canada Warbler Trends in MarylandNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Canada Warbler in Maryland. See the full index history below.

Canada Warbler Population Forecast in Maryland

If the recent trend holds, Canada Warbler in Maryland is projected to fall about 63% by 2029 — from 0.12 in 2024 to a central estimate of 0.04 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±68.7%, with 80% of held-out values landing inside the 95% band.

-63%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 →
0.00–0.1695% 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 →
±68.7%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 in Maryland is projected to fall about 63% by 2029 — from 0.12 in 2024 to a central estimate of 0.04 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±68.7%, 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 →
20250.050.000.16
20260.050.000.16
20270.050.000.16
20280.040.000.16
20290.040.000.16

Canada Warbler Survey Routes in Maryland

Routes recording Canada Warbler in Maryland.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Jennings220241995
Floyd120241966
Mt Nebo119911969
Vindex120041966
Oldtown120242024
Accident120171993
Accident 2120242018

Canada Warbler Population Trend in Other States

connecticutgeorgiaindianamainemassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.