Mating, fighting, birthing elephant seals delight crowds at Año Nuevo State Park.

PESCADERO >> The first thing you notice is the sound, as you approach the beach at Año Nuevo State Park during the peak of elephant seal breeding season.

To an untrained ear, it's a din of honking, bleating, farting, screeching and wailing.

But to northern elephant seal enthusiasts, it's a symphony of voices, a purpose for each call - the most distinctive of which is the 2-ton bull's throbbing drumbeat of a roar.