BirdAnalyst
Species · BCR 22 · BBS 2026 Release · 1966–2025

Purple Martin In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieAerial insectivores

Purple Martin in Eastern Tallgrass Prairie has edged down: down 17% on the route-weighted index since 1968.

-17%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 →
265Routes 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 →

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 42% by 2030 — from 5.5 in 2025 to a central estimate of 3.2 (95% range 0.86–5.5). A 5-year backtest shows a typical error of ±43.9%, with 60% of held-out values landing inside the 95% band.

-42%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 →
3.2Projected 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 →
0.86–5.595% 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 →
±43.9%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 42% by 2030 — from 5.5 in 2025 to a central estimate of 3.2 (95% range 0.86–5.5). A 5-year backtest shows a typical error of ±43.9%, with 60% 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 →
20263.20.895.6
20273.20.885.6
20283.20.875.5
20293.20.865.5
20303.20.865.5

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 →
DecaturINDIANA872025
FultonOHIO452025
WabashINDIANA422025
KeetonvilleOKLAHOMA322022
Ash RidgeOHIO302021
KearneyMISSOURI292025
BradburyILLINOIS282025
WashingtonMISSOURI281977
AuburnMISSOURI282025
Witts StationINDIANA272025
CollinsvilleOKLAHOMA272021
EubanksILLINOIS262025
AthensvilleILLINOIS242025
KalidaOHIO242025
SenecaILLINOIS222025
ExlineIOWA212025
New HamptonMISSOURI202025
EmdenMISSOURI202024
DoverMISSOURI192025
RobinsonILLINOIS182023
GalesburgKANSAS172025
JanesvilleILLINOIS162025
ThorntownINDIANA162025
Camp PointILLINOIS152025
SherburnvillILLINOIS142023

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