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Species · Massachusetts · BBS 2025 Release · 1966–2024

Least Flycatcher Population Trend in Massachusetts

All statesAerial insectivores

Least Flycatcher in Massachusetts has edged down: down 25% on the route-weighted index since 1968.

-25%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 →
26Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Least Flycatcher 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 Least Flycatcher in Massachusetts. See the full index history below.

Least Flycatcher Population Forecast in Massachusetts

If the recent trend holds, Least Flycatcher in Massachusetts is projected to fall about 51% by 2029 — from 2.0 in 2024 to a central estimate of 0.97 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±33.3%, with 100% of held-out values landing inside the 95% band.

-51%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 →
0.97Projected 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 →
0.00–2.495% 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 →
±33.3%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, Least Flycatcher in Massachusetts is projected to fall about 51% by 2029 — from 2.0 in 2024 to a central estimate of 0.97 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±33.3%, with 100% 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 →
20251.10.002.5
20261.10.002.5
20271.10.002.5
20281.00.002.4
20290.970.002.4

Least Flycatcher Survey Routes in Massachusetts

Routes recording Least Flycatcher 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 →
N Orange820241968
Cummington 2820242015
Sheffield720221969
Hancock720151997
Chesterfield620241967
Monterey520242019
Ware River420221993
Cummington420141968
E Pepperell319941966
Princeton219761969
Belchertown220241967
S Barre220221968
Pittsfield220161969
N. Andover219981997
Marion119991969
Prattville120031966
Brockton119951972
Newburyport120091967
Maynard119951967
Littleton120141967
N Oxford119941968
Cape Cod Ns119951995
Warren120091968
Cheshire119941969
Holden120161977

Least Flycatcher Population Trend in Other States

alaskaarkansascaliforniacoloradoconnecticutgeorgiaidahoillinoisindianaiowakentuckymainemarylandmichiganminnesotamissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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