As many as 100 of the birds dotted the waterline back to Puckeys Estate.

A lifeguard on duty said it was an annual occurrence as the birds, short-tailed shearwaters, migrate 10,000km from the Bering Sea, between Alaska and Japan, to Australian shores in late September to nest.

Some of the birds become exhausted by the long flight, fall out of the sky into the water and wash up on the beaches.

The lifeguard said some birds had also washed up on North Wollongong Beach. He said the locations where the dead birds are washed up will vary depending on the wind direction and the swell.