Species · Louisiana · BBS 2025 Release · 1966–2024
Forster's Tern Population Trend in Louisiana
Forster's Tern in Louisiana has collapsed: down 86% on the route-weighted index since 1973.
-86%Since 1973
20Routes In State
43Years
Notable Forster's Tern Trends in Louisiana
long arc declinecomputed index
Forster's Tern has collapsed in Louisiana: down 86% on the route-weighted index since 1973.
Forster's Tern Population Forecast in Louisiana
If the recent trend holds, Forster's Tern in Louisiana is projected to fall about 100% by 2029 — from 0.27 in 2024 to a central estimate of 0.00 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±63.9%, with 100% of held-out values landing inside the 95% band.
-100%Change by 2029
0.00Projected 2029 index
0.00–1.995% range
±63.9%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.01 | 0.00 | 1.9 |
| 2026 | 0.00 | 0.00 | 1.9 |
| 2027 | 0.00 | 0.00 | 1.9 |
| 2028 | 0.00 | 0.00 | 1.9 |
| 2029 | 0.00 | 0.00 | 1.9 |
Forster's Tern Survey Routes in Louisiana
| Creole | 61 | 1987 | 1970 |
| Sabine Nwr | 15 | 2008 | 1989 |
| Sabine Nwr 2 | 14 | 2017 | 2009 |
| Belair | 11 | 2013 | 1995 |
| Junior | 10 | 1991 | 1987 |
| Woodlawn | 10 | 2019 | 2019 |
| Forked Island | 10 | 2024 | 2008 |
| Grand Isle | 9 | 2018 | 2010 |
| Glencoe | 6 | 2014 | 2014 |
| Gran Chenier | 5 | 1973 | 1970 |
| Carlisle | 3 | 1987 | 1987 |
| Hackberry | 2 | 2016 | 1976 |
| Mayflower | 2 | 2002 | 1995 |
| Forked Island 2 | 2 | 2010 | 2010 |
| Kaplan | 2 | 1999 | 1999 |
| Ltl Chenier 2 | 2 | 2011 | 2010 |
| Berwick | 2 | 2010 | 2000 |
| Lafitte | 1 | 1988 | 1988 |
| River Road | 1 | 1997 | 1997 |
| Ltl Chenier | 1 | 2024 | 1986 |
Forster's Tern Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.