BirdAnalyst
Species · BCR 24 · BBS 2025 Release · 1966–2024

Purple Martin In Central Hardwoods

All regionsCentral HardwoodsAerial insectivores

Purple Martin in Central Hardwoods has surged: up 108% on the route-weighted index since 1968.

+108%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 →
164Routes 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 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 →

Purple Martin has surged in Central Hardwoods: up 108% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Purple Martin in Central Hardwoods is projected to stay roughly flat through 2029, near 8.8 (95% range 6.3–11). A 5-year backtest shows a typical error of ±20.8%, with 100% of held-out values landing inside the 95% band.

+2%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 →
8.8Projected 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 →
6.3–1195% 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 →
±20.8%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, Purple Martin in Central Hardwoods is projected to stay roughly flat through 2029, near 8.8 (95% range 6.3–11). A 5-year backtest shows a typical error of ±20.8%, 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 →
20258.66.111
20268.66.211
20278.76.211
20288.76.311
20298.86.311

Routes In Central Hardwoods

Routes recording Purple Martin in Central Hardwoods.
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 →
SyracuseMISSOURI582024
PeytonsvilleTENNESSEE512024
NewberryINDIANA402024
KeysburgKENTUCKY382024
WhitewaterMISSOURI372024
GlenTENNESSEE362024
EugeneMISSOURI292024
ColcordOKLAHOMA272022
FarwellARKANSAS262018
VevayINDIANA252024
CelestineINDIANA232024
Valhermoso SpgsALABAMA222010
ReedsMISSOURI222023
DrakesboroKENTUCKY212003
MillerMISSOURI212024
BelknapILLINOIS202024
BremenILLINOIS192024
HustonvilleKENTUCKY192024
GlencoeKENTUCKY192018
CentertownMISSOURI192024
YorkILLINOIS182024
Lebanon JunctionKENTUCKY182024
AkersMISSOURI182024
Kings MtnKENTUCKY172024
Cole CampMISSOURI171990

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