BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Purple Martin In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieAerial insectivores

Purple Martin in Eastern Tallgrass Prairie has declined: down 27% on the route-weighted index since 1968.

-27%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 →
259Routes 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 →

No notable trend signals for Purple Martin in Eastern Tallgrass Prairie. See the full index history below.

Purple Martin In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Purple Martin in Eastern Tallgrass Prairie is projected to fall about 49% by 2029 — from 5.9 in 2024 to a central estimate of 3.0 (95% range 0.74–5.3). A 5-year backtest shows a typical error of ±39.6%, with 80% of held-out values landing inside the 95% band.

-49%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 →
3.0Projected 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 →
0.74–5.395% 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 →
±39.6%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 Eastern Tallgrass Prairie is projected to fall about 49% by 2029 — from 5.9 in 2024 to a central estimate of 3.0 (95% range 0.74–5.3). A 5-year backtest shows a typical error of ±39.6%, with 80% 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 →
20253.10.795.3
20263.10.785.3
20273.00.775.3
20283.00.755.3
20293.00.745.3

Routes In Eastern Tallgrass Prairie

Routes recording Purple Martin in Eastern Tallgrass Prairie.
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 →
ExlineIOWA492024
BrookvilleINDIANA392024
RensselaerMISSOURI322024
KeetonvilleOKLAHOMA322022
Ash RidgeOHIO302021
DecaturINDIANA292024
AuburnMISSOURI292024
WashingtonMISSOURI281977
WabashINDIANA272024
CollinsvilleOKLAHOMA272021
SenecaILLINOIS262024
BerneINDIANA262024
FultonOHIO242024
New HamptonMISSOURI232024
West LibertyIOWA202024
SticklervillMISSOURI202024
EmdenMISSOURI202024
BradburyILLINOIS192024
HumboldtILLINOIS192024
Mascoutah LkILLINOIS192024
PawneeILLINOIS182024
RobinsonILLINOIS182023
GalesburgKANSAS182024
AthensvilleILLINOIS172024
EubanksILLINOIS172024

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