BirdAnalyst
Species · Maryland · BBS 2025 Release · 1966–2024

Common Tern Population Trend in Maryland

All statesWetland birds

Common Tern in Maryland has fallen sharply: down 54% on the route-weighted index since 1968.

-54%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 →
7Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
13YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Tern Trends in MarylandNotable 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 Maryland: down 54% on the route-weighted index since 1968.

Common Tern Survey Routes in Maryland

Routes recording Common Tern in Maryland.
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 →
Sinepuxent319711967
Jones319681966
Berlin319881988
Madison219871987
Piney Neck119671967
Golden Hill119831978
Newark119821966

Common Tern Population Trend in Other States

alabamaalaskaconnecticutdelawarefloridaidahoindianalouisianamainemassachusettsmichiganminnesotamontananew-jerseynew-yorknorth-carolinanorth-dakotaohiorhode-islandsouth-dakotatexasvermontvirginiawashingtonwisconsinwyoming

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