BirdAnalyst
Species · BCR 23 · BBS 2025 Release · 1966–2024

Purple Martin In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionAerial insectivores

Purple Martin in Prairie Hardwood Transition has fallen sharply: down 72% on the route-weighted index since 1968.

-72%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 →
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 →

Purple Martin has fallen sharply in Prairie Hardwood Transition: down 72% 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 2029 — from 2.9 in 2024 to a central estimate of 0.00 (95% range 0.00–2.9). A 5-year backtest shows a typical error of ±155.4%, with 40% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–2.995% 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 →
±155.4%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 2029 — from 2.9 in 2024 to a central estimate of 0.00 (95% range 0.00–2.9). A 5-year backtest shows a typical error of ±155.4%, with 40% 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 →
20250.000.002.9
20260.000.002.9
20270.000.002.9
20280.000.002.9
20290.000.002.9

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 →
MiddleburyINDIANA612024
PackertownINDIANA362004
EdwardsMINNESOTA362024
LagrangeINDIANA272024
KielWISCONSIN262022
GraytownOHIO241984
PardeevilleWISCONSIN212024
HollandWISCONSIN202024
Packertown 2INDIANA162024
HoltMICHIGAN162024
NapoleonOHIO162024
MottvilleMICHIGAN122018
Whitewater 2MINNESOTA112019
LimestoneOHIO112023
ClintonvilleWISCONSIN112008
ManitowocWISCONSIN92024
Columbia CtyINDIANA82022
PrattvilleMICHIGAN72021
PettysvilleMICHIGAN71979
Chippewa Lk.MICHIGAN72024
OmroWISCONSIN72001
LakevilleINDIANA62024
HartlandMICHIGAN62001
St StephenMINNESOTA62016
New LondonMINNESOTA62024

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