BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Herring Gull Population Analysis

LaridaeWetland birdsLarus argentatus

Herring Gull has collapsed: down 77% on the route-weighted index since 1968.

-77%Since 1968TrendPercent 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 →
413RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Herring Gull

The Herring Gull (Larus argentatus) is a North American member of the Gulls, Terns & Skimmers (Laridae). In this analysis it is grouped with the wetland birds.

Size
8.5–31.5 in long (22–80 cm) — a long-winged waterbird (typical for the family)
Habitat
Marshes, ponds, lakeshores and other freshwater wetlands.
Diet
Aquatic invertebrates, small fish, frogs and plant matter.
Range
Recorded on 413 Breeding Bird Survey routes across 33 states, most concentrated in the New England / Mid-Atlantic Coast.
Family
Laridae · Wetland birds

Notable Herring Gull TrendsNotable 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 →

Herring Gull has collapsed in surveyed states: down 77% on the route-weighted index since 1968.

Herring Gull Population Forecast

If the recent trend holds, Herring Gull is projected to fall about 100% by 2030 — from 0.20 in 2025 to a central estimate of 0.00 (95% range 0.00–0.72). A 5-year backtest shows a typical error of ±159.3%, with 60% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.7295% 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 →
±159.3%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 is projected to fall about 100% by 2030 — from 0.20 in 2025 to a central estimate of 0.00 (95% range 0.00–0.72). A 5-year backtest shows a typical error of ±159.3%, with 60% of held-out values landing inside the 95% band.19662030
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 →
20260.000.000.72
20270.000.000.72
20280.000.000.72
20290.000.000.72
20300.000.000.72

Where the Herring Gull Is Detected

BBS routes recording Herring Gull, sized by most recent count.

Herring Gull Population Trend by State

Herring Gull population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabama-76%19725
Alaska-97%197259
Californiainsufficient datan/a5
Coloradoinsufficient datan/a1
Connecticut-5%197111
Delaware-80%196812
Florida-59%19689
Idahoinsufficient datan/a2
Illinois+173%19864
Indiana+142%19935
Kansasinsufficient datan/a1
Louisianainsufficient datan/a3
Maine-90%196842
Maryland+391%196821
Massachusetts-98%196818
Michigan-96%196840
Minnesota-54%197117
Montanainsufficient datan/a2
New Hampshire-100%196812
New Jersey56×196922
New York-95%196845
North Carolina-77%19738
Ohio-10%197014
Oregoninsufficient datan/a3
Pennsylvaniainsufficient datan/a5
Rhode Island-98%19695
South Carolinainsufficient datan/a1
Texasinsufficient datan/a2
Vermont-31%19695
Virginia-87%19689
Washingtoninsufficient datan/a1
West Virginiainsufficient datan/a1
Wisconsin-83%196823

Herring Gull Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Herring Gull population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
BCR 2-68%19983
BCR 4-2%197643
Northern Pacific Rainforest-98%197222
Boreal Hardwood Transition-97%196854
Lower Great Lakes / St. Lawrence Plain-4%196927
Atlantic Northern Forest-90%196867
Eastern Tallgrass Prairie+25%198611
Prairie Hardwood Transition12×196830
Southeastern Coastal Plain-93%196819
Appalachian Mountains-68%197312
New England / Mid-Atlantic Coast-31%1968104
Peninsular Florida+167%20095

Herring Gull Conservation Status

Our route-weighted index shows it down about 77% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.