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Species · Massachusetts · BBS 2026 Release · 1966–2025

Blackburnian Warbler Population Trend in Massachusetts

All statesForest birds

Blackburnian Warbler in Massachusetts has surged: up 202% on the route-weighted index since 1968.

+202%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 →
19Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Blackburnian Warbler Trends in MassachusettsNotable 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 →

Blackburnian Warbler has surged in Massachusetts: up 202% on the route-weighted index since 1968.

Blackburnian Warbler Population Forecast in Massachusetts

If the recent trend holds, Blackburnian Warbler in Massachusetts is projected to rise about 97% by 2030 — from 0.94 in 2025 to a central estimate of 1.8 (95% range 0.97–2.7). A 5-year backtest shows a typical error of ±87.9%, with 20% of held-out values landing inside the 95% band.

+97%Change by 2030TrendPercent 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 →
1.8Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.97–2.795% 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 →
±87.9%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, Blackburnian Warbler in Massachusetts is projected to rise about 97% by 2030 — from 0.94 in 2025 to a central estimate of 1.8 (95% range 0.97–2.7). A 5-year backtest shows a typical error of ±87.9%, with 20% of held-out values landing inside the 95% band.19662030
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 →
20261.80.882.6
20271.80.912.7
20281.80.932.7
20291.80.952.7
20301.80.972.7

Blackburnian Warbler Survey Routes in Massachusetts

Routes recording Blackburnian Warbler in Massachusetts.
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 →
Pittsfield1420161969
Cummington920141968
Chesterfield820251967
Sheffield520221971
Cummington 2320252015
Hancock320151997
Princeton219761970
Belchertown220251973
Warren219841975
Holden219891977
Marion119931993
Ware River120221994
Littleton119721972
E Pepperell119881966
S Barre120211978
N Orange120251968
Cheshire119921971
Monterey120252019
Warren 2120112011

Blackburnian Warbler Population Trend in Other States

connecticutgeorgiaindianamainemarylandmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.