BirdAnalyst
Species · BCR 37 · BBS 2026 Release · 1966–2025

Purple Martin In Gulf Coastal Prairie

All regionsGulf Coastal PrairieAerial insectivores

Purple Martin in Gulf Coastal Prairie has risen sharply: up 58% on the route-weighted index since 1969.

+58%Since 1969TrendPercent 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 →
48Routes 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 risen sharply in Gulf Coastal Prairie: up 58% on the route-weighted index since 1969.

Purple Martin In Gulf Coastal Prairie Population Forecast

If the recent trend holds, Purple Martin in Gulf Coastal Prairie is projected to rise about 56% by 2030 — from 14 in 2025 to a central estimate of 22 (95% range 6.2–38). A 5-year backtest shows a typical error of ±74.5%, with 80% of held-out values landing inside the 95% band.

+56%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 →
22Projected 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 →
6.2–3895% 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 →
±74.5%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 Gulf Coastal Prairie is projected to rise about 56% by 2030 — from 14 in 2025 to a central estimate of 22 (95% range 6.2–38). A 5-year backtest shows a typical error of ±74.5%, with 80% of held-out values landing inside the 95% band.19672030
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 →
2026225.838
2027225.938
2028226.038
2029226.138
2030226.238

Routes In Gulf Coastal Prairie

Routes recording Purple Martin in Gulf Coastal 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 →
Forked Island 2LOUISIANA942011
Ltl Chenier 2LOUISIANA832011
Hackberry 2LOUISIANA602025
JuniorLOUISIANA471991
LafitteLOUISIANA421991
Loyola BeachTEXAS382009
IndianolaTEXAS362024
Oyster LakeTEXAS362025
Bayside 3TEXAS342025
GlencoeLOUISIANA332018
WoodlawnLOUISIANA322021
Ville PlatteLOUISIANA312019
Forked IslandLOUISIANA242025
Gran ChenierLOUISIANA231982
KatyTEXAS222025
Ltl ChenierLOUISIANA202025
CreoleLOUISIANA181987
Lag AtascosaTEXAS182025
Loyola Beach 2TEXAS182025
HackberryLOUISIANA162016
RichardLOUISIANA162025
Grand IsleLOUISIANA142019
MamouLOUISIANA131982
EstherLOUISIANA132025
MauriceLOUISIANA132024

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