Rhinoceros Auklet
Rhinoceros Auklet has held roughly steady: down 1% on the route-weighted index since 1976.
About the Rhinoceros Auklet
The Rhinoceros Auklet (Cerorhinca monocerata) is a North American member of the Auks, Murres & Puffins (Alcidae). In this analysis it is grouped with the seabirds.
- Size
- 8–17.5 in long (20–45 cm) — a compact seabird (typical for the family)
- Habitat
- Open ocean and coastlines, coming ashore mainly to nest in colonies.
- Diet
- Fish, squid and other marine animals caught at or below the surface.
- Range
- Recorded on 6 Breeding Bird Survey routes across 2 states, most concentrated in the Northern Pacific Rainforest.
- Family
- Alcidae · Seabirds
Notable Rhinoceros Auklet Trends
No notable trend signals for Rhinoceros Auklet. See the full index history below.
Rhinoceros Auklet Population Forecast
If the recent trend holds, Rhinoceros Auklet is projected to stay roughly flat through 2020, near 0.00 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±798.1%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2016 | 0.00 | 0.00 | 0.02 |
| 2017 | 0.00 | 0.00 | 0.02 |
| 2018 | 0.00 | 0.00 | 0.02 |
| 2019 | 0.00 | 0.00 | 0.02 |
| 2020 | 0.00 | 0.00 | 0.02 |
Where the Rhinoceros Auklet Is Detected
BBS routes recording Rhinoceros Auklet, sized by most recent count.
Rhinoceros Auklet Population Trend by State
| California | insufficient data | n/a | 1 |
| Washington | -59% | 1976 | 5 |
Rhinoceros Auklet Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Northern Pacific Rainforest | -19% | 1976 | 6 |
Rhinoceros Auklet Conservation Status
Our route-weighted index has held roughly steady since 1976.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.