BirdAnalyst
Species · BCR 13 · BBS 2026 Release · 1966–2025

Bobolink In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainGrassland birds

Bobolink in Lower Great Lakes / St. Lawrence Plain has fallen sharply: down 68% on the route-weighted index since 1968.

-68%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 →
86Routes 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 →
59YearsYears 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 →

Bobolink has fallen sharply in Lower Great Lakes / St. Lawrence Plain: down 68% on the route-weighted index since 1968.

Bobolink In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Bobolink in Lower Great Lakes / St. Lawrence Plain is projected to stay roughly flat through 2030, near 4.0 (95% range 0.00–8.7). A 5-year backtest shows a typical error of ±45.7%, with 100% of held-out values landing inside the 95% band.

+6%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 →
4.0Projected 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 →
0.00–8.795% 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 →
±45.7%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, Bobolink in Lower Great Lakes / St. Lawrence Plain is projected to stay roughly flat through 2030, near 4.0 (95% range 0.00–8.7). A 5-year backtest shows a typical error of ±45.7%, with 100% 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 →
20264.80.129.5
20274.60.009.3
20284.40.009.1
20294.20.008.9
20304.00.008.7

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Bobolink in Lower Great Lakes / St. Lawrence Plain.
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 →
West BangorNEW-YORK791999
NashvilleNEW-YORK342018
WatertownNEW-YORK272012
WaddingtonNEW-YORK271998
WaylandOHIO232017
NaplesNEW-YORK222025
DuanesburgNEW-YORK202025
Cherry HillNEW-YORK202019
AusterlitzNEW-YORK152025
PhiladelphiaNEW-YORK152025
BranchportNEW-YORK142024
RandolphNEW-YORK132018
E YoungstownNEW-YORK132023
OneidaNEW-YORK132010
RomulusNEW-YORK122000
FowlerNEW-YORK121968
North PownalVERMONT122025
SheridanNEW-YORK112025
OgdensburgNEW-YORK112025
EllenburgNEW-YORK112006
N WilmurtNEW-YORK101998
N VictoryNEW-YORK101972
Ballston LkNEW-YORK91995
AkeleyPENNSYLVANIA91979
MendonNEW-YORK82024

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