BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Northern Rough-winged Swallow In Gulf Coastal Prairie

All regionsGulf Coastal PrairieAerial insectivores

Northern Rough-winged Swallow in Gulf Coastal Prairie has fallen sharply: down 64% on the route-weighted index since 1972.

-64%Since 1972TrendPercent 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 →
23Routes 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 →
41YearsYears 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 declinecomputed 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 →

Northern Rough-winged Swallow has fallen sharply in Gulf Coastal Prairie: down 64% on the route-weighted index since 1972.

Forecast

If the recent trend holds, Northern Rough-winged Swallow in Gulf Coastal Prairie is projected to stay roughly flat through 2029, near 1.2 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±1749.5%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
1.2Projected 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 →
0.00–4.695% 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 →
±1749.5%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, Northern Rough-winged Swallow in Gulf Coastal Prairie is projected to stay roughly flat through 2029, near 1.2 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±1749.5%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20251.10.004.6
20261.10.004.6
20271.20.004.6
20281.20.004.6
20291.20.004.6

Routes In Gulf Coastal Prairie

Routes recording Northern Rough-winged Swallow 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 →
MamouLOUISIANA301982
Moon LakeTEXAS121995
Hinkles FerTEXAS62012
BaysideTEXAS61996
Bayside 3TEXAS62013
KatyTEXAS32005
Ville PlatteLOUISIANA21997
WoodlawnLOUISIANA22011
Lag AtascosaTEXAS22018
PetronilaTEXAS22014
Rock IslandTEXAS22016
JuniorLOUISIANA11991
LafitteLOUISIANA11967
GlencoeLOUISIANA12014
EstherLOUISIANA12009
KaplanLOUISIANA12015
Ltl Chenier 2LOUISIANA12010
Forked IslandLOUISIANA12024
Vinton 2LOUISIANA12022
IndianolaTEXAS11992
WinnieTEXAS11994
San PedroTEXAS12018
Loyola Beach 2TEXAS12011

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