BirdAnalyst
Species · BCR 13 · BBS 2025 Release · 1966–2024

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 66% on the route-weighted index since 1968.

-66%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 →
58YearsYears 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 66% 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 rise about 13% by 2029 — from 3.8 in 2024 to a central estimate of 4.3 (95% range 0.00–9.0). A 5-year backtest shows a typical error of ±42.4%, with 100% of held-out values landing inside the 95% band.

+13%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 →
4.3Projected 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 →
0.00–9.095% 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 →
±42.4%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 rise about 13% by 2029 — from 3.8 in 2024 to a central estimate of 4.3 (95% range 0.00–9.0). A 5-year backtest shows a typical error of ±42.4%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20255.10.399.8
20264.90.199.6
20274.70.009.4
20284.50.009.2
20294.30.009.0

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
DuanesburgNEW-YORK272024
WatertownNEW-YORK272012
WaddingtonNEW-YORK271998
WaylandOHIO232017
Cherry HillNEW-YORK202019
NaplesNEW-YORK152024
BranchportNEW-YORK142024
RandolphNEW-YORK132018
E YoungstownNEW-YORK132023
OneidaNEW-YORK132010
RomulusNEW-YORK122000
FowlerNEW-YORK121968
EllenburgNEW-YORK112006
N WilmurtNEW-YORK101998
PhiladelphiaNEW-YORK102024
N VictoryNEW-YORK101972
Ballston LkNEW-YORK91995
OgdensburgNEW-YORK92024
AkeleyPENNSYLVANIA91979
MendonNEW-YORK82024
SheridanNEW-YORK82024
GarrettsvileOHIO81991
Valley CityOHIO82017

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