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

Broad-winged Hawk Population Trend in Massachusetts

All statesGeneralists

Broad-winged Hawk in Massachusetts has surged: up 99% on the route-weighted index since 1970.

+99%Since 1970TrendPercent 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 →
28Routes 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 →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Broad-winged Hawk 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 →

Broad-winged Hawk has surged in Massachusetts: up 99% on the route-weighted index since 1970.

Broad-winged Hawk Population Forecast in Massachusetts

If the recent trend holds, Broad-winged Hawk in Massachusetts is projected to fall about 27% by 2029 — from 0.47 in 2024 to a central estimate of 0.34 (95% range 0.05–0.63). A 5-year backtest shows a typical error of ±35.8%, with 100% of held-out values landing inside the 95% band.

-27%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 →
0.34Projected 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 →
0.05–0.6395% 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 →
±35.8%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, Broad-winged Hawk in Massachusetts is projected to fall about 27% by 2029 — from 0.47 in 2024 to a central estimate of 0.34 (95% range 0.05–0.63). A 5-year backtest shows a typical error of ±35.8%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.330.040.62
20260.330.040.62
20270.330.040.63
20280.340.040.63
20290.340.050.63

Broad-winged Hawk Survey Routes in Massachusetts

Routes recording Broad-winged Hawk 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 →
Brockton420172017
Ware River420221993
Mansfield220241969
Chesterfield220241969
Holden220231978
Hancock220152014
E Dennis120091978
Marion120231969
Wellfleet119951979
Prattville120092009
Newburyport120211971
Maynard120171969
Littleton120101968
N Oxford120211968
E Pepperell119831981
Belchertown120161971
Warren120091968
S Barre120241972
N Orange120231972
Cummington120141972
Cheshire119881973
Pittsfield120061971
Sheffield120001976
Monterey120232022
Wellfleet 2120182018

Broad-winged Hawk Population Trend in Other States

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

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