HUNDREDS of dead birds found washed ashore at Middleton Beach over the weekend were exhausted short-tailed shearwaters, which fly thousands of kilometres to breed across southern Australia.
More than 20 million shearwaters, also known as mutton birds, make the journey to southern Australia, including South Australia, from the north Pacific each year but many run out of reserves during the journey and die - often washing up on islands near Ceduna, or along the South Coast.
Department of Environment, Water and Natural Resources marine scientist Brad Page said the birds arrived within a day or two of each other.
"The islands off Ceduna are the hot spots for shearwaters in SA," he said.
"They travel enormous distances every year and unless they get enough to eat on the journey, they can easily die from starvation.
"Any food shortage along the way can have fatal effects, and birds often make it back to southern Australia with almost no energy reserves.