BirdAnalyst
Species · BCR 12 · BBS 2026 Release · 1966–2025

Franklin's Gull In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionWetland birds

Franklin's Gull in Boreal Hardwood Transition has collapsed: down 82% on the route-weighted index since 1994.

-82%Since 1994TrendPercent 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 →
3Routes 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 →

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 →

Franklin's Gull has collapsed in Boreal Hardwood Transition: down 82% on the route-weighted index since 1994.

Franklin's Gull In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Franklin's Gull in Boreal Hardwood Transition is projected to fall about 61% by 2030 — from 0.12 in 2025 to a central estimate of 0.05 (95% range 0.00–0.95). A 5-year backtest shows a typical error of ±881.2%, with 100% of held-out values landing inside the 95% band.

-61%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 →
0.05Projected 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 →
0.00–0.9595% 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 →
±881.2%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 in Boreal Hardwood Transition is projected to fall about 61% by 2030 — from 0.12 in 2025 to a central estimate of 0.05 (95% range 0.00–0.95). A 5-year backtest shows a typical error of ±881.2%, with 100% of held-out values landing inside the 95% band.19822030
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 →
20260.110.001.0
20270.100.001.0
20280.080.000.98
20290.070.000.97
20300.050.000.95

Routes In Boreal Hardwood Transition

Routes recording Franklin's Gull in Boreal Hardwood Transition.
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 →
WarroadMINNESOTA82025
LudeMINNESOTA12025
GreenbushMINNESOTA12018

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.