Species · Idaho · BBS 2025 Release · 1966–2024
Black-headed Grosbeak Population Trend in Idaho
Black-headed Grosbeak in Idaho has surged: up 323% on the route-weighted index since 1971.
+323%Since 1971
53Routes In State
54Years
Notable Black-headed Grosbeak Trends in Idaho
long arc increasecomputed index
Black-headed Grosbeak has surged in Idaho: up 323% on the route-weighted index since 1971.
Black-headed Grosbeak Population Forecast in Idaho
If the recent trend holds, Black-headed Grosbeak in Idaho is projected to rise about 33% by 2029 — from 1.7 in 2024 to a central estimate of 2.3 (95% range 1.6–3.0). A 5-year backtest shows a typical error of ±15.7%, with 100% of held-out values landing inside the 95% band.
+33%Change by 2029
2.3Projected 2029 index
1.6–3.095% range
±15.7%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 2.2 | 1.4 | 2.9 |
| 2026 | 2.2 | 1.5 | 2.9 |
| 2027 | 2.2 | 1.5 | 3.0 |
| 2028 | 2.3 | 1.5 | 3.0 |
| 2029 | 2.3 | 1.6 | 3.0 |
Black-headed Grosbeak Survey Routes in Idaho
| Cascade | 11 | 1984 | 1974 |
| Gifford | 9 | 2017 | 1971 |
| Joel | 9 | 2024 | 1989 |
| Rochat Divde | 8 | 2023 | 1993 |
| Magic Mtn | 6 | 2024 | 1987 |
| Featherville | 6 | 2024 | 1989 |
| Picabo | 6 | 2021 | 2002 |
| Naples | 5 | 2024 | 1978 |
| Lolo Pass | 5 | 2019 | 1992 |
| Challis | 5 | 2024 | 1976 |
| Glenns Ferry | 5 | 1986 | 1986 |
| Coolin | 5 | 2024 | 1986 |
| Baldy Mountain | 5 | 2016 | 2013 |
| Sawtooth City 2 | 5 | 2023 | 2017 |
| Pierce | 5 | 2005 | 1990 |
| Mivoden | 4 | 2023 | 1977 |
| Squirrel | 4 | 2024 | 1972 |
| Nezperce | 3 | 2012 | 1996 |
| Golden | 3 | 2015 | 1987 |
| N Fork Cda R | 3 | 2018 | 1993 |
| Centerville | 3 | 2019 | 1982 |
| Mud Lake | 3 | 2014 | 2008 |
| Cabarton | 3 | 2023 | 1985 |
| Avery | 2 | 2023 | 1979 |
| Springfield | 2 | 2017 | 1969 |
Black-headed Grosbeak Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.