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

Purple Martin In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionAerial insectivores

Purple Martin in Prairie Hardwood Transition has fallen sharply: down 70% on the route-weighted index since 1968.

-70%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 →
143Routes 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 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 →

Purple Martin has fallen sharply in Prairie Hardwood Transition: down 70% on the route-weighted index since 1968.

Purple Martin In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Purple Martin in Prairie Hardwood Transition is projected to fall about 100% by 2030 — from 2.6 in 2025 to a central estimate of 0.00 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±150.3%, with 20% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–3.095% 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 →
±150.3%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, Purple Martin in Prairie Hardwood Transition is projected to fall about 100% by 2030 — from 2.6 in 2025 to a central estimate of 0.00 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±150.3%, with 20% 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 →
20260.000.003.0
20270.000.003.0
20280.000.003.0
20290.000.003.0
20300.000.003.0

Routes In Prairie Hardwood Transition

Routes recording Purple Martin 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 →
MiddleburyINDIANA382025
PackertownINDIANA362004
EdwardsMINNESOTA362024
Packertown 2INDIANA342025
GraytownOHIO241984
LagrangeINDIANA192025
PardeevilleWISCONSIN182025
NapoleonOHIO172025
HoltMICHIGAN142025
VickeryOHIO132025
MottvilleMICHIGAN122018
LoraineWISCONSIN122025
HollandWISCONSIN122025
Whitewater 2MINNESOTA112019
ClintonvilleWISCONSIN112008
ManitowocWISCONSIN92024
KielWISCONSIN92025
Columbia CtyINDIANA82022
CascoWISCONSIN82025
PrattvilleMICHIGAN72021
PettysvilleMICHIGAN71979
OmroWISCONSIN72001
LakevilleINDIANA62024
HartlandMICHIGAN62001
New LondonMINNESOTA62024

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