BREEDING BIOLOGY OF THE PARAKEET AUKLET COMPARED TO OTHER CREVICE-NESTING SPECIES AT BULDIR-ISLAND, ALASKA

In 1991, we examined the nesting habitat, nesting chronology, reproduc tive performance, and chick growth rates of the Parakeet Auklet (Cyclo rrhynchus psittacula) at Buldir Island, Alaska. These auklets nested i n rock crevices on vegetated talus slopes, in areas of mixed rock and soil, on vertical cliffs, and among large beach boulders above the hig h tide line. They also dug earth burrows in areas of deep soil. The ti ming of nesting events was later in Parakeet Auklets, and their reprod uctive output (0.51 chicks fledged per egg laid) was slightly lower, t han those of three species of crevice-nesting Aethia auklets at Buldir . Parakeet Auklets usually incubated their eggs in 24 h shifts. On ave rage, Parakeet Auklet chicks weighed 27 g at hatching, gained 8.6 g d- 1 during the linear growth period, peaked at 253 g, and eventually dro pped to 208 g (about 84% of adult mass) at fledging, ca. 36 days after hatching. The nesting chronology and reproductive performance of Para keet Auklets subjected to two different levels of disturbance were sim ilar.