Species · BCR 4 · BBS 2025 Release · 1966–2024
American Tree Sparrow In BCR 4
American Tree Sparrow in BCR 4 has surged: up 227% on the route-weighted index since 1977.
+227%Since 1977
44Routes In Region
44Years
Notable Signals
long arc increasecomputed index
American Tree Sparrow has surged in BCR 4: up 227% on the route-weighted index since 1977.
Forecast
If the recent trend holds, American Tree Sparrow in BCR 4 is projected to fall about 23% by 2029 — from 7.3 in 2024 to a central estimate of 5.6 (95% range 0.00–15). A 5-year backtest shows a typical error of ±34.6%, with 100% of held-out values landing inside the 95% band.
-23%Change by 2029
5.6Projected 2029 index
0.00–1595% range
±34.6%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 5.8 | 0.00 | 15 |
| 2026 | 5.8 | 0.00 | 15 |
| 2027 | 5.7 | 0.00 | 15 |
| 2028 | 5.7 | 0.00 | 15 |
| 2029 | 5.6 | 0.00 | 15 |
Routes In BCR 4
| Savage | ALASKA | 114 | 2024 |
| Toklat | ALASKA | 94 | 2024 |
| Pinoche Tral (Short) | ALASKA | 48 | 1984 |
| Maclaren | ALASKA | 46 | 2024 |
| Cantwell | ALASKA | 22 | 2021 |
| Monahan | ALASKA | 20 | 2021 |
| Kobuk River (Short) | ALASKA | 13 | 1992 |
| Circle | ALASKA | 10 | 2018 |
| Porcupine R. | ALASKA | 10 | 1994 |
| Chatanika R | ALASKA | 6 | 2015 |
| Manley Ht Sp | ALASKA | 6 | 2022 |
| Paxson Lake | ALASKA | 6 | 1997 |
| Nebesna | ALASKA | 5 | 1975 |
| Donelly Dome | ALASKA | 5 | 2017 |
| Tatalina | ALASKA | 5 | 2010 |
| Eagle | ALASKA | 4 | 2024 |
| Chistochina | ALASKA | 4 | 2023 |
| Tangle Lakes | ALASKA | 4 | 1987 |
| Willow | ALASKA | 3 | 1996 |
| Moose Creek | ALASKA | 3 | 2021 |
| Kanuti Lake | ALASKA | 3 | 2022 |
| Slana | ALASKA | 2 | 2008 |
| Kalifonsky | ALASKA | 2 | 1982 |
| Hatcher Pass | ALASKA | 2 | 2011 |
| Lake Louise | ALASKA | 2 | 2011 |
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.