BirdAnalyst
Species · BCR 23 · BBS 2026 Release · 1966–2025

Tree Swallow In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionAerial insectivores

Tree Swallow in Prairie Hardwood Transition has surged: up 148% on the route-weighted index since 1968.

+148%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 →
161Routes 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 →
59YearsYears 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 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 →

Tree Swallow has surged in Prairie Hardwood Transition: up 148% on the route-weighted index since 1968.

Tree Swallow In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Tree Swallow in Prairie Hardwood Transition is projected to rise about 65% by 2030 — from 6.2 in 2025 to a central estimate of 10 (95% range 5.1–15). A 5-year backtest shows a typical error of ±101.5%, with 0% of held-out values landing inside the 95% band.

+65%Change by 2030TrendPercent 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 →
10Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
5.1–1595% 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 →
±101.5%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, Tree Swallow in Prairie Hardwood Transition is projected to rise about 65% by 2030 — from 6.2 in 2025 to a central estimate of 10 (95% range 5.1–15). A 5-year backtest shows a typical error of ±101.5%, with 0% of held-out values landing inside the 95% band.19662030
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 →
20269.94.815
202710.04.915
2028104.915
2029105.015
2030105.115

Routes In Prairie Hardwood Transition

Routes recording Tree Swallow in Prairie 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 →
EdwardsMINNESOTA452024
EllisINDIANA422024
OmroWISCONSIN372001
LapeerMICHIGAN342025
LagrangeINDIANA252025
CohoctahMICHIGAN252025
KnappMINNESOTA232025
Sherburne NrMINNESOTA202025
New LondonMINNESOTA192024
LakevilleINDIANA172017
FestinaIOWA172025
MatherWISCONSIN172023
HoltMICHIGAN162025
RichmondMICHIGAN152024
GlenwoodMINNESOTA152019
HamburgMICHIGAN142000
St StephenMINNESOTA142025
AshbyMINNESOTA142021
Big Blue LkMICHIGAN132025
Whitewater 2MINNESOTA132019
HollandWISCONSIN132025
RochesterMICHIGAN122025
MinnetonkaMINNESOTA122025
HolwayWISCONSIN121989
Omro 2WISCONSIN122025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.