BirdAnalyst
Species · Massachusetts · BBS 2025 Release · 1966–2024

Black-throated Blue Warbler Population Trend in Massachusetts

All statesForest birds

Black-throated Blue Warbler in Massachusetts has increased: up 49% on the route-weighted index since 1969.

+49%Since 1969TrendPercent 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 →
17Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-throated Blue 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 →

No notable trend signals for Black-throated Blue Warbler in Massachusetts. See the full index history below.

Black-throated Blue Warbler Population Forecast in Massachusetts

If the recent trend holds, Black-throated Blue Warbler in Massachusetts is projected to rise about 85% by 2029 — from 0.87 in 2024 to a central estimate of 1.6 (95% range 0.72–2.5). A 5-year backtest shows a typical error of ±97.6%, with 60% of held-out values landing inside the 95% band.

+85%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 →
1.6Projected 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 →
0.72–2.595% 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 →
±97.6%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, Black-throated Blue Warbler in Massachusetts is projected to rise about 85% by 2029 — from 0.87 in 2024 to a central estimate of 1.6 (95% range 0.72–2.5). A 5-year backtest shows a typical error of ±97.6%, with 60% of held-out values landing inside the 95% band.19672029
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 →
20251.60.672.4
20261.60.682.4
20271.60.702.5
20281.60.712.5
20291.60.722.5

Black-throated Blue Warbler Survey Routes in Massachusetts

Routes recording Black-throated Blue 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 →
Pittsfield2220161968
Cummington620141968
Monterey520242019
Chesterfield420241967
Ware River320221993
Hancock320151997
Cheshire219931982
Sheffield220131969
Cummington 2220242015
Maynard119701970
Princeton119741972
E Pepperell119701970
Belchertown120241978
S Barre120222014
N Orange120241969
Holden120081980
Warren 2120172017

Black-throated Blue Warbler Population Trend in Other States

connecticutgeorgiamainemarylandmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinapennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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