Species · Wisconsin · BBS 2025 Release · 1966–2024
Common Tern Population Trend in Wisconsin
Common Tern in Wisconsin has collapsed: down 86% on the route-weighted index since 1969.
-86%Since 1969
3Routes In State
21Years
Notable Common Tern Trends in Wisconsin
long arc declinecomputed index
Common Tern has collapsed in Wisconsin: down 86% on the route-weighted index since 1969.
Common Tern Population Forecast in Wisconsin
If the recent trend holds, Common Tern in Wisconsin is projected to fall about 100% by 2018 — from 0.15 in 2013 to a central estimate of 0.00 (95% range 0.00–0.89). A 5-year backtest shows a typical error of ±5116.5%, with 20% of held-out values landing inside the 95% band.
-100%Change by 2018
0.00Projected 2018 index
0.00–0.8995% range
±5116.5%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2014 | 0.00 | 0.00 | 0.89 |
| 2015 | 0.00 | 0.00 | 0.89 |
| 2016 | 0.00 | 0.00 | 0.89 |
| 2017 | 0.00 | 0.00 | 0.89 |
| 2018 | 0.00 | 0.00 | 0.89 |
Common Tern Survey Routes in Wisconsin
| Washington I | 13 | 2013 | 1967 |
| Phillips | 4 | 2004 | 2004 |
| Omro | 1 | 1980 | 1967 |
Common Tern Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.