The spectacle put on by these birds was nothing short of amazing. With an estimated (in my opinion probably low) 90,000 birds passing by us in an endless stream not too far offshore, it was a real sight. These birds are considered near-threatened as their numbers have dropped considerably. Habitat loss, pollution, and probably over-harvesting (the Maori still kill them in their native New Zealand) have lead to this decline. These birds are very long-distance travelers, following a circular route from their breeding islands in the south Pacific/Atlantic, traveling north up the western side of the Pacific and Atlantic Oceans. They begin breeding in October, and incubate their young for about 54 days. Once the chick hatches, the parents raise their chick for 86 to 109 days. At the end of the nesting season in March–May, they disperse, reaching subarctic waters in June–July where they cross from west to east, then returning south down the eastern side of the oceans in September–October, reaching the breeding colonies in November. They do not migrate as a flock, but as single individuals, congregating only where food is found. In California, there were enormous schools of anchovies, so that's what they were feeding on. Recent tagging experiments have shown that birds breeding in New Zealand may travel 46,000 miles in a year, reaching Japan, Alaska and California, averaging more than 300 miles per day. They can dive over 200 feet in search of food. Truly astounding birds!
On August 18, 1961, the Santa Cruz Sentinel reported that thousands of crazed sooty shearwaters were sighted on the shores of North Monterey Bay in California, regurgitating anchovies, flying into objects, and dying on the streets. The incident sparked the interest of local resident Alfred Hitchcock, along with a story of spooky bird behavior by British writer Daphne du Maurier, helping to inspire Hitchcock's 1963 thriller The Birds.
It is believed their behavior was caused by a toxic algae in the water. There was a housing boom in the 60s in Monterey and it is believed that leaky septic tanks helped feed the toxic plankton.