Species: Cerorhinca monocerata
Encyclopedia of Puget Sound
A large, chunky, seabird with a large head and bill and a short thick neck; upperparts are blackish brown, with paler sides, neck, and throat; belly white, grading into dark breast; adults in breeding plumage (acquired in winter) have two prominent white plume streaks on each side of the head (indistinct in basic plumage) and a yellow, upward-directed horn at the base of the orange or yellowish bill (horn is absent in nonbreeding plumage); immatures lack the horn and the white head plumes, and the bill is dusky and the eyes are darker; average length 38 cm (NGS 1983).
Science Review:
Articles:
Were the islands half full of auklets or were they half empty? One scientist offers an insider's view of a newly published study of two Pacific seabird colonies. He says having good data for the paper was key, but finding the right title didn't hurt.

Where do Protection Island's rhinoceros auklets go to find their food? Scientists hope GPS tags will offer new insight into the bird's still mysterious foraging behavior. Biologist and science writer Eric Wagner reports from the field.

Scientists are still trying to understand what caused the deaths of thousands of rhinoceros auklets in the Salish Sea in 2016. Some studies point to disease as a central factor in that incident and potentially other large seabird die-offs along the coast. That is prompting a deeper look at what makes these birds sick, and how local populations are faring. We followed a group of researchers as they gave a health checkup to a breeding colony of rhinoceros auklets on Protection Island.

More than 70 percent of the seabird population of Puget Sound nests on a single island in the Strait of Juan de Fuca. That includes a massive colony of rhinoceros auklets that has drawn the interest of scientists and birders alike. Our writer Eric Wagner visited the island this summer and reports on a long-term study of the auklets that is revealing new information about the health of seabirds in the Salish Sea.

New research presented at the 2014 Salish Sea Ecosystem Conference shows that some of the greatest dangers to Puget Sound marine life come from our common, everyday activities. These pervasive sources of pollution are so woven into our lives that they are almost invisible to us, but it’s becoming impossible to ignore their effects.

A report from the Puget Sound Ecosystem Monitoring Program provides an overview of 2013 marine water quality and conditions in Puget Sound from comprehensive monitoring and observing programs.

A December 2013 report identifies marine and terrestrial bird species for use as indicators within the Puget Sound Partnership's "Vital Signs" for ecosystem health.

The Puget Sound Marine Waters 2012 Overview from the Puget Sound Ecosystem Monitoring Program synthesizes conditions measured in 2012 and has been expanded to include observations on seabirds that rely on marine waters. Read an excerpt below, or download the full report.
A paper in the May 2013 issue of The Condor [115(2):356–365, 2013] describes a repeatable and statistically robust approach to monitoring burrow nesting seabirds in the Salish Sea and the California Current that can be applied at single- or multi-island scales. The approach can be applied to both relatively common and important members of the seabird community like the Rhinoceros Auklet and to species of conservation concern like the Tufted Puffin.

More than 70 bird species regularly utilize Puget Sound during some or all stages of their life histories, but only a portion of these are actively being investigated.

Protection Island, a National Wildlife Refuge in the Strait of Juan de Fuca, provides important habitat for seabirds and marine mammals.


Classification
Aves
Charadriiformes
Alcidae
Cerorhinca
NatureServe
Classification
Ecology and Life History
A large, chunky, seabird with a large head and bill and a short thick neck; upperparts are blackish brown, with paler sides, neck, and throat; belly white, grading into dark breast; adults in breeding plumage (acquired in winter) have two prominent white plume streaks on each side of the head (indistinct in basic plumage) and a yellow, upward-directed horn at the base of the orange or yellowish bill (horn is absent in nonbreeding plumage); immatures lack the horn and the white head plumes, and the bill is dusky and the eyes are darker; average length 38 cm (NGS 1983).
Conservation Status
LC - Least concern