BirdAnalyst
Species · BCR 21 · BBS 2025 Release · 1966–2024

Swainson's Warbler In Oaks and Prairies

All regionsOaks and PrairiesForest birds

Swainson's Warbler in Oaks and Prairies has surged: up 166% on the route-weighted index since 1999.

+166%Since 1999TrendPercent 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 →
7Routes 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 →
20YearsYears 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 →

Swainson's Warbler has surged in Oaks and Prairies: up 166% on the route-weighted index since 1999.

Swainson's Warbler In Oaks and Prairies Population Forecast

If the recent trend holds, Swainson's Warbler in Oaks and Prairies is projected to fall about 51% by 2029 — from 0.11 in 2024 to a central estimate of 0.05 (95% range 0.02–0.09). A 5-year backtest shows a typical error of ±42.1%, with 80% of held-out values landing inside the 95% band.

-51%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 →
0.05Projected 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 →
0.02–0.0995% 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 →
±42.1%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, Swainson's Warbler in Oaks and Prairies is projected to fall about 51% by 2029 — from 0.11 in 2024 to a central estimate of 0.05 (95% range 0.02–0.09). A 5-year backtest shows a typical error of ±42.1%, with 80% of held-out values landing inside the 95% band.19962029
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 →
20250.050.010.08
20260.050.010.09
20270.050.010.09
20280.050.010.09
20290.050.020.09

Routes In Oaks and Prairies

Routes recording Swainson's Warbler in Oaks and Prairies.
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 →
HearneTEXAS32024
GauseTEXAS11997
Oak Grove 2TEXAS12011
CayugaTEXAS12024
BonnerTEXAS12007
Wills PointTEXAS12012
PaigeTEXAS12024

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