BirdAnalyst
Species · BCR 29 · BBS 2025 Release · 1966–2024

Ring-billed Gull In Piedmont

All regionsPiedmontWetland birds

Ring-billed Gull in Piedmont has collapsed: down 93% on the route-weighted index since 1971.

-93%Since 1971TrendPercent 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 →
8Routes 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 →
23YearsYears 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 →

Ring-billed Gull has collapsed in Piedmont: down 93% on the route-weighted index since 1971.

Forecast

If the recent trend holds, Ring-billed Gull in Piedmont is projected to stay roughly flat through 2019, near 0.17 (95% range 0.00–0.99). A 5-year backtest shows a typical error of ±3072.6%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2019TrendPercent 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 →
0.17Projected 2019 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.9995% 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 →
±3072.6%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, Ring-billed Gull in Piedmont is projected to stay roughly flat through 2019, near 0.17 (95% range 0.00–0.99). A 5-year backtest shows a typical error of ±3072.6%, with 100% of held-out values landing inside the 95% band.19682019
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 →
20150.180.001.0
20160.180.001.0
20170.180.001.00
20180.170.001.00
20190.170.000.99

Routes In Piedmont

Routes recording Ring-billed Gull in Piedmont.
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 →
TheodoreMARYLAND341970
Mount JoyPENNSYLVANIA231996
Big IslandVIRGINIA51990
EmmitsburgMARYLAND21990
Upper XrdsMARYLAND12007
MooresvilleNORTH-CAROLINA11968
ArcolaNORTH-CAROLINA12014
FlayNORTH-CAROLINA11997

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