BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Northern Rough-winged Swallow In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionAerial insectivores

Northern Rough-winged Swallow in Boreal Hardwood Transition has fallen sharply: down 53% on the route-weighted index since 1968.

-53%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 →
85Routes In RegionSurvey 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 SignalsNotable 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 declinecomputed 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 →

Northern Rough-winged Swallow has fallen sharply in Boreal Hardwood Transition: down 53% on the route-weighted index since 1968.

Northern Rough-winged Swallow In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Northern Rough-winged Swallow in Boreal Hardwood Transition is projected to rise about 53% by 2029 — from 0.12 in 2024 to a central estimate of 0.18 (95% range 0.00–0.55). A 5-year backtest shows a typical error of ±488%, with 100% of held-out values landing inside the 95% band.

+53%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 →
0.18Projected 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 →
0.00–0.5595% 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 →
±488%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, Northern Rough-winged Swallow in Boreal Hardwood Transition is projected to rise about 53% by 2029 — from 0.12 in 2024 to a central estimate of 0.18 (95% range 0.00–0.55). A 5-year backtest shows a typical error of ±488%, 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 →
20250.210.000.58
20260.200.000.57
20270.200.000.56
20280.190.000.56
20290.180.000.55

Routes In Boreal Hardwood Transition

Routes recording Northern Rough-winged Swallow in Boreal Hardwood Transition.
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 →
Eagle RiverWISCONSIN182011
Crystal FlsMICHIGAN92022
Walloon Lake 2MICHIGAN92007
GilmanWISCONSIN92022
LudeMINNESOTA72015
Maple GroveMICHIGAN61996
BigforkMINNESOTA51996
Brocky LakeMICHIGAN42008
CathroMICHIGAN41995
Popple RiverWISCONSIN42022
CavourWISCONSIN42021
Bear LakeMICHIGAN32008
IronsMICHIGAN31985
Skegemog PtMICHIGAN32011
Hubbard LakeMICHIGAN31986
Frederic 2MICHIGAN32008
Seney NwrMICHIGAN31992
Mille LacsMINNESOTA32018
Pine RiverMINNESOTA32024
ChaffeyWISCONSIN32015
Grand ViewWISCONSIN31986
CouderayWISCONSIN32016
WausaukeeWISCONSIN32016
Weirgor SpringsWISCONSIN32016
Ned LakeMICHIGAN21988

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