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Species · Louisiana · BBS 2025 Release · 1966–2024

Gull-billed Tern Population Trend in Louisiana

All statesWetland birds

Gull-billed Tern in Louisiana has edged down: down 18% on the route-weighted index since 1997.

-18%Since 1997TrendPercent 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 →
5Routes 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 →
16YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gull-billed Tern Trends in LouisianaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Gull-billed Tern in Louisiana. See the full index history below.

Gull-billed Tern Survey Routes in Louisiana

Routes recording Gull-billed Tern in Louisiana.
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 →
Grand Isle220142010
Sabine Nwr219961996
Belair120221997
Gran Chenier119711971
Forked Island120242024

Gull-billed Tern Population Trend in Other States

alabamacaliforniadelawarefloridageorgiamarylandmississippinorth-carolinasouth-carolinatexasvirginia

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