reporter: carefully and quietly, joan carles palerm approaches the flamingo, watching from afar. doesn't want to startle the bird. flamingos are his passion. joan: flamingos are odd-looking, highly unusual birds. so it's easy to get people interested in them, even those who don't care about environmental protection. reporter: palerm is happy to see the birds flock to ibiza's las salinas salt flats. he's counted hundreds of them already, and their numbers have been on the rise in recent years. that's good news for the spanish island, but mass tourism is posing a danger to the birds. joan: las salinas has become too busy for them to bring up their young. in april, when the breeding season begins, most adult birds fly away to reproduce. reporter: because in spring, flocks of tourists descend on ibiza, which has become known as the mediterranean's number one party destination. as visitor numbers soar, the environment pays the price. and most holiday-makers couldn't care less. a road leads straight through the ses salines national park to a highly popular beach, which is teeming with