BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Franklin's Gull In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionWetland birds

Franklin's Gull in Boreal Hardwood Transition has collapsed: down 81% on the route-weighted index since 1994.

-81%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 →
18YearsYears 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 81% 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 52% by 2027 — from 0.21 in 2022 to a central estimate of 0.10 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±340.8%, with 100% of held-out values landing inside the 95% band.

-52%Change by 2027TrendPercent 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 →
0.10Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.095% 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 →
±340.8%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 52% by 2027 — from 0.21 in 2022 to a central estimate of 0.10 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±340.8%, with 100% of held-out values landing inside the 95% band.19822027
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 →
20230.170.001.1
20240.150.001.1
20250.130.001.1
20260.120.001.0
20270.100.001.0

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 →
WarroadMINNESOTA122022
LudeMINNESOTA42022
GreenbushMINNESOTA12018

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