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

Chimney Swift Population Trend in Massachusetts

All statesAerial insectivores

Chimney Swift in Massachusetts has fallen sharply: down 56% on the route-weighted index since 1968.

-56%Since 1968
32Routes In State
58Years

Notable Chimney Swift Trends in Massachusetts

long arc declinecomputed index

Chimney Swift has fallen sharply in Massachusetts: down 56% on the route-weighted index since 1968.

Chimney Swift Population Forecast in Massachusetts

If the recent trend holds, Chimney Swift in Massachusetts is projected to fall about 20% by 2029 — from 5.6 in 2024 to a central estimate of 4.5 (95% range 1.1–7.8). A 5-year backtest shows a typical error of ±20.3%, with 100% of held-out values landing inside the 95% band.

-20%Change by 2029
4.5Projected 2029 index
1.1–7.895% range
±20.3%Backtest error
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 index95% low95% high
20254.81.58.2
20264.71.48.1
20274.61.38.0
20284.61.27.9
20294.51.17.8

Chimney Swift Survey Routes in Massachusetts

Routes recording Chimney Swift in Massachusetts.
E Pepperell2719941966
Warren 21920242010
Prattville1820191966
Warren1820091968
N Orange1320241968
Holden1320241977
Mansfield1020241968
Monterey1020242019
Hancock820141997
Wellfleet719971966
Marion620241966
Newburyport620221967
E Dennis520211967
Brockton520191967
Belchertown520241967
Cheshire519931969
Pittsfield520161967
Maynard420221967
S Barre320241968
Gay Head320222017
N Oxford220241968
Chesterfield220241967
Ware River220191994
Chilmark119831969
Littleton120161967

Chimney Swift Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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