The proud parents feted their daughter in atypical Hollywood fashion, at a small bash for friends and family, reported Us magazine.
An eyewitness said there were only about 20 people on the guest list, many of whom were from Mendes' large brood.
"It was a quiet and casual party, not the typical celebrity 1st birthday blowout with vendors and other celebrity guests," the onlooker said.
"It looked like it was just their simple style and more about family and close friends coming together to celebrate Esmeralda."
"Some people brought wrapped gifts, including clothes and toys," the eyewitness said. "One guest arrived carrying a rocking horse, and another had colorful plastic balls to fill a ball pit."
Mendes, 41, gave birth to Esmeralda on September 12, 2014.
