BirdAnalyst
Species · BCR 17 · BBS 2025 Release · 1966–2024

Franklin's Gull In Badlands and Prairies

All regionsBadlands and PrairiesWetland birds

Franklin's Gull in Badlands and Prairies has collapsed: down 96% on the route-weighted index since 1970.

-96%Since 1970TrendPercent 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 →
23Routes 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 →
28YearsYears 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 Badlands and Prairies: down 96% on the route-weighted index since 1970.

Franklin's Gull In Badlands and Prairies Population Forecast

If the recent trend holds, Franklin's Gull in Badlands and Prairies is projected to rise about 11× by 2029 — from 0.13 in 2024 to a central estimate of 1.4 (95% range 0.00–6.4). A 5-year backtest shows a typical error of ±245.2%, with 80% of held-out values landing inside the 95% band.

11×Change by 2029TrendPercent 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 →
1.4Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–6.495% 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 →
±245.2%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 Badlands and Prairies is projected to rise about 11× by 2029 — from 0.13 in 2024 to a central estimate of 1.4 (95% range 0.00–6.4). A 5-year backtest shows a typical error of ±245.2%, with 80% of held-out values landing inside the 95% band.19682029
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 →
20251.40.006.3
20261.40.006.4
20271.40.006.4
20281.40.006.4
20291.40.006.4

Routes In Badlands and Prairies

Routes recording Franklin's Gull in Badlands and Prairies.
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 →
HighwoodMONTANA9002016
Fort PierreSOUTH-DAKOTA1001998
ChamberlainSOUTH-DAKOTA442011
Dunn CenterNORTH-DAKOTA201968
DickinsonNORTH-DAKOTA92013
RoundupMONTANA62024
Wheat BasinMONTANA62023
CircleMONTANA31993
TobaccoNORTH-DAKOTA31993
Ft ThompsonSOUTH-DAKOTA31990
LeroyMONTANA22024
LaplantSOUTH-DAKOTA21990
Cedar PassSOUTH-DAKOTA22002
JordanMONTANA12016
Two DotMONTANA12000
ShawmutMONTANA12024
ForsythMONTANA11994
Maynard CouleeMONTANA12023
BowmanNORTH-DAKOTA11973
GorhamNORTH-DAKOTA12002
Glen UllinNORTH-DAKOTA11990
S. PioneerSOUTH-DAKOTA12022
BillWYOMING11999

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