A seabird that develops a horn-like projection on its bill during breeding.
Breeding adults are gray, with pale facial plumes and a pale horn on the bill. Nonbreeding adults lack the horn.
Across the northeastern Pacific, auklets that wintered farther from their colony tended to lay later the next spring. Researchers fitted geolocation tags to 109 birds at 12 colonies from southern California to the eastern Aleutian Islands. Winter centroids ranged from under 100 km to over 2,500 km from the colony. Longer distances were associated with later laying even after colony differences were considered.
Higher-latitude colonies also had later laying dates, and latitude had the stronger relationship. The study observed associations; it did not show that distance itself causes a delay. Its results link an individual bird’s winter location with spring breeding timing across this part of the Pacific.
IUCN Red List · Least Concern (LC) · Global species-level assessment
BirdLife International’s global IUCN assessment listed the Rhinoceros Auklet as Least Concern on 7 August 2018, while recording a decreasing population trend. The category and trend apply to the species globally; they do not describe the population or recent conditions at every breeding colony. Continued colony-level monitoring can help show where and how the decline is occurring.