The government of Peru is investigating the deaths of more than 500 pelicans along a 70km (40-mile) stretch of the country's northern coast.
Officials say most appeared to have died on shore over the past few days.
Scientists have also found the carcasses of 54 boobies, several sea lions and a turtle.
They were found in the same region where some 800 dolphins washed ashore earlier this year. The cause of their death is still being investigated.