BirdAnalyst
Species · BCR 28 · BBS 2025 Release · 1966–2024

Herring Gull In Appalachian Mountains

All regionsAppalachian MountainsWetland birds

Herring Gull in Appalachian Mountains has fallen sharply: down 68% on the route-weighted index since 1973.

-68%Since 1973TrendPercent 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 →
12Routes 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 →
19YearsYears 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 Herring Gull in Appalachian Mountains. See the full index history below.

Forecast

If the recent trend holds, Herring Gull in Appalachian Mountains is projected to stay roughly flat through 2026, near 0.00 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±461.7%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2026TrendPercent 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 →
0.00Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2495% 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 →
±461.7%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, Herring Gull in Appalachian Mountains is projected to stay roughly flat through 2026, near 0.00 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±461.7%, with 100% of held-out values landing inside the 95% band.19662026
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 →
20220.000.000.24
20230.000.000.24
20240.000.000.24
20250.000.000.24
20260.000.000.24

Routes In Appalachian Mountains

Routes recording Herring Gull in Appalachian Mountains.
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 →
SomersNEW-YORK81977
ClearfieldPENNSYLVANIA31999
MidvaleNEW-JERSEY22000
DoverNEW-JERSEY21994
Pine GroveALABAMA11966
DrydenNEW-YORK11999
GainesvilleNEW-YORK11990
BirminghamOHIO11993
GreentownPENNSYLVANIA12003
WaterstreetPENNSYLVANIA11981
BrunnervillePENNSYLVANIA11975
RuthbelleWEST-VIRGINIA12021

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