The currency is also called the Quetzal, and the bird appears in flight on each note, as below.
Sadly we didn't see any real live Quetzals, but brought home some hand made beaded versions for the Christmas tree!
Historically, the ancient Mayans used the feathers of the resplendent quetzal as decoration and these can be seen in some of the stone carvings in Mayan sites such as Tikal in Guatemala and Palenque in Mexico. It's always good to have a local guide who can point out these things, as these ancient sculpted details, like the birds, are often very difficult to spot! On the right of this stone stella, if you look very carefully, you can see the tail feathers of the Qutezal which adorned the headress of Pakal, a Mayan emperor.