Huītzilōpōchtli could take the form ('nagual') of hummingbird or eagle, was always depicted in a hummingbird feather headdress. In fact, his name is huītzilin "hummingbird" and ōpōchtli for "south".
Aztec warriors who died in battle were reincarnated as hummingbirds.
Huītzilōpōchtli was also the sun god and founder deity of the Aztec people, guiding them to Tenochtitlan as a hummingbird, then as an eagle perched on a cactus.
It was his demands for daily sustenance in the form of human sacrifices (tlaxcaltiliztli) that made the Aztec temples so bloody.
Technically, the Mexican flag depicts the event of Huītzilōpōchtli perching on a cactus to indicate where to settle the city of Tenochtitlan, now Mexico City.
It could just as easily have been a blood-soaked hummingbird.
i wish i could affirm that hummingbird instead is in the coat of arms of Mexico's neighbor country
but no, it's the quetzal, which gave name to the Mayan counterpart god, Quetzalcoatl ("quetzal-like snake")
