The town of Pateros, near Laguna de Bay, built its identity on duck raising and balut-making, and its name is often traced to 'pato', the Spanish word for duck.
A fertilized duck egg is incubated for around two to three weeks, just long enough for an embryo to begin forming, then boiled and eaten warm straight from the shell with a pinch of salt or splash of vinegar. Vendors carry them in baskets or steam them at carts, often calling out through the streets after dark.