Artificial nest boxes for burrow-nesting seabirds, Rhinoceros Auklet (Cerorhinca monocerata) were employed to study their breeding ecology easily and safely. Three types of nest boxes were set in the colony in Teuri Island in the northern part of Hokkaido. No detrimental effects on growth rate and fledging success rate were observed among the chicks raised in artificial nest boxes (growth rate: 8.34±1.42g d-1 in 1995 and 8.13±0.67g d-1 in 1996, mean±S. D., fledging success: 78.6% in 1995 and 88.5% in 1996) in comparison with those raised in natural burrows (growth rate: 8.14±1.47g d-1 in 1995 and 6.96±1.12 g d-1 in 1996, fledging success: 77.8% in 1995 and 75.0% in 1996). Although there were no apparent differences of occupation ratio between 3 types of artificial nest boxes, the plastic basket type was recommended as it has good ventilation and durability.
