Species · Maine · BBS 2025 Release · 1966–2024
Green Heron Population Trend in Maine
Green Heron in Maine has collapsed: down 77% on the route-weighted index since 1968.
-77%Since 1968
22Routes In State
35Years
Notable Green Heron Trends in Maine
long arc declinecomputed index
Green Heron has collapsed in Maine: down 77% on the route-weighted index since 1968.
Green Heron Population Forecast in Maine
If the recent trend holds, Green Heron in Maine is projected to fall about 100% by 2028 — from 0.06 in 2023 to a central estimate of 0.00 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±196.2%, with 40% of held-out values landing inside the 95% band.
-100%Change by 2028
0.00Projected 2028 index
0.00–0.1395% range
±196.2%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2024 | 0.00 | 0.00 | 0.13 |
| 2025 | 0.00 | 0.00 | 0.13 |
| 2026 | 0.00 | 0.00 | 0.13 |
| 2027 | 0.00 | 0.00 | 0.13 |
| 2028 | 0.00 | 0.00 | 0.13 |
Green Heron Survey Routes in Maine
| Westbrook | 2 | 1989 | 1980 |
| Kittery Pt | 2 | 1985 | 1966 |
| Brooks | 2 | 1977 | 1977 |
| Charleston | 2 | 1991 | 1991 |
| Cambridge | 2 | 2001 | 1977 |
| Cape Neddick | 1 | 2023 | 1973 |
| Newcastle | 1 | 1993 | 1972 |
| Turner | 1 | 1991 | 1991 |
| South Arm | 1 | 1975 | 1975 |
| Otisfield Gr | 1 | 1986 | 1966 |
| Hartford | 1 | 2004 | 1975 |
| Bowdoin Ctr | 1 | 1986 | 1979 |
| Manchester | 1 | 1982 | 1971 |
| East Troy | 1 | 1994 | 1994 |
| Harmony | 1 | 1990 | 1990 |
| Hermon | 1 | 1981 | 1981 |
| Eastbrook | 1 | 1979 | 1979 |
| Medway | 1 | 2000 | 2000 |
| Forest Sta | 1 | 1968 | 1968 |
| Washburn | 1 | 1990 | 1979 |
| Cornville | 1 | 2019 | 2019 |
| Rome | 1 | 1998 | 1998 |
Green Heron Population Trend in Other States
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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.