Site description (2001 baseline):
Northern Fulmars are common around factory ships during late summer and early fall. Flocks of between 5,000 and 10,000 birds have been observed over both Amphitrite and Swiftsure banks. These birds are thought to be a mixture of non-breeding adults, failed breeders and immature birds. Shearwaters are also abundant in late spring, early summer, and again from September through mid-October, the non-breeding season for Sooty and Short-tailed shearwaters. On one occasion a flock of approximately 12,000 Sooty Shearwaters was seen over Swiftsure Bank in June.
California Gulls can be seen between May and November, but progressively become more abundant as the summer and fall advance. A single large flock that was estimated to contain 15,000 birds was seen over Swiftsure Bank in August 1989; it is thought that the birds were associated with factory ships. This species is the most abundant species in the fall. The largest flock in this season was recorded in September 1986 when between 10,000 and 12,000 were seen feeding on schools of small fish in Swiftsure Bank. Sabines Gulls may be seen between May and October, but they are most abundant in late August and September. Large flocks of this species were seen at Swiftsure Bank in September 1986 (975) and August 1989 (620). These numbers are almost certainly over 1% of the Canadian Sabines Gull population and may also be over 1% of the unknown North American population.
Other birds recorded here in high numbers include: Cassins Auklets (6,000 at Amphitrite Bank in August 1986), Common Murres, Rhinoceros Auklets, Tufted Puffins, Herring, Thayers and Glaucous-winged gulls Black-legged Kittiwakes, jaegers, phalaropes, and other procellariids.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Amphitrite and Swiftsure Banks (Canada). Downloaded from
https://datazone.birdlife.org/site/factsheet/amphitrite-and-swiftsure-banks-iba-canada on 24/12/2024.