BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Franklin's Gull Population Analysis

LaridaeWetland birdsLeucophaeus pipixcan

Franklin's Gull has surged: up 217% on the route-weighted index since 1969.

+217%Since 1969TrendPercent 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 →
189RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years 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 Franklin's Gull

The Franklin's Gull (Leucophaeus pipixcan) 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 189 Breeding Bird Survey routes across 12 states, most concentrated in the Prairie Potholes.
Family
Laridae · Wetland birds

Notable Franklin's 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 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 →

Franklin's Gull has surged in surveyed states: up 217% on the route-weighted index since 1969.

Franklin's Gull Population Forecast

If the recent trend holds, Franklin's Gull is projected to stay roughly flat through 2030, near 0.93 (95% range 0.21–1.6). A 5-year backtest shows a typical error of ±31.3%, with 80% of held-out values landing inside the 95% band.

+5%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 →
0.93Projected 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 →
0.21–1.695% 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 →
±31.3%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, Franklin's Gull is projected to stay roughly flat through 2030, near 0.93 (95% range 0.21–1.6). A 5-year backtest shows a typical error of ±31.3%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.890.181.6
20270.900.181.6
20280.910.191.6
20290.920.201.6
20300.930.211.6

Where the Franklin's Gull Is Detected

BBS routes recording Franklin's Gull, sized by most recent count.

Franklin's Gull Population Trend by State

Franklin's 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 →
California+45%19933
Coloradoinsufficient datan/a1
Idaho+129%197219
Kansasinsufficient datan/a3
Minnesota-94%197125
Montana+242%197033
Nebraskainsufficient datan/a6
North Dakota+791%197039
Oregon-92%197713
South Dakota-38%196926
Utah-61%197213
Wyoming-95%19908

Franklin's Gull Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Franklin's 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 →
Great Basin+34%197240
Northern Rockies+270%197421
Prairie Potholes+161%196986
Boreal Hardwood Transition-82%19943
Badlands and Prairies-93%197023

Franklin's Gull Conservation Status

Our route-weighted index shows it up about 217% since 1969.

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