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

Common Tern In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainWetland birds

Common Tern in Lower Great Lakes / St. Lawrence Plain has fallen sharply: down 64% on the route-weighted index since 1975.

-64%Since 1975TrendPercent 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 →
6Routes 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 →
12YearsYears 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 →

Common Tern has fallen sharply in Lower Great Lakes / St. Lawrence Plain: down 64% on the route-weighted index since 1975.

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Common Tern 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 →
MiddlefieldOHIO151975
OgdensburgNEW-YORK22024
MacdougallNEW-YORK11997
Cicero CtrNEW-YORK12023
N VictoryNEW-YORK11967
Grand IsleVERMONT12012

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