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GAP Analysis Predicted Distribution Map

Rhinoceros Auklet (Cerorhinca monocerata)

Species Code: CEMO

Click to enlarge Range map

= Core Habitat
= Marginal Habitat

Breeding Range Map
The green area shows the predicted habitats for breeding only. The habitats were identified using 1991 satellite imagery, Breeding Bird Atlas (BBA), other datasets and experts throughout the state, as part of the Washington Gap Analysis Project. Habitats used during non-breeding months and migratory rest-stops were not mapped.

Metadata (Data about data or how the map was made)

Click to enlarge distribution map

Other maps & Information:
  • Breeding Bird Atlas
  • NatureMapping observations
    during breeding season
  • NatureMapping observations
    throughout the year

This species is locally common on islands of the outer coast and inland marine waters.

Good habitats in the core areas of use included coastal habitats (but not estuaries) in zones adjacent to the coast, limited to the islands (Protection I., Smith/Minor I., Tatoosh I., East Bodelteh I., Alexander I., and Destruction I.).

Rhinoceros Auklets are the second-most abundant breeding seabird in Washington, constituting 23.6% of all breeding seabirds. Their numbers typically fluctuate annually, based on food supply and climatic events. El Nino/Southern Oscillation events tend to decrease seabird breeding productivity. Documents estimate 27,000 Rhinoceros Auklet burrows on Protection Island, which makes it the largest Washington colony. It has been found that burrow densities were higher on coastal islands than on islands in inland waters due to the presence of shrubby slopes on coastal islands (compared to grassy flats), yet colonies on inland waters had higher breeding success due to greater availability of prey (fish). Rhinoceros Auklets formerly bred on Whidbey Island, where the species and its eggs were first collected and described. Numbers on Protection Island declined steadily from a 1980 population of 34,000 to the 1992 population of 12,000, despite an ample supply of Sand-lance in the straits. On Smith and Minor Islands, 1992 numbers had declined due to competition with Double-crested Cormorants. Outer-coast colonies appeared to be stable as of 1992. Elsewhere on the west coast, this species is recovering well from the 1983 El Nino/Southern Oscillation event. Gill-netting also contributes to mortality for this species.

Translated from the Washington Gap Analysis Bird Volume by Uchenna Bright
Text edited by Gussie Litwer
Webpage designed by Dave Lester