That at least suggests they might have originated here, but McGuire thinks that's unlikely, because the oldest fossils of modern hummers have been found in Europe. So if they did originate here, how did they get to Europe?
This is not the first mystery hummingbirds have handed to scholars.
The fact that hummers can hover while feeding on a flower, and fly backwards, sideways, up or down, has long perplexed scientists. It took the latest technology in wind tunnels and high speed cameras to figure that one out.
The hummingbird doesn't flap its wings up and down, like other birds. Its wings oscillate in a circular motion, forming a figure eight, and the bird gets lift both from its downstroke -- like all birds -- but also from its upstroke.
Scientists at Los Alamos National Laboratory and a number of other high tech institutions had to build a robotic hummer to figure out how.
As they fly, the wings form a vortex, sort of like a whirlpool in air, on the leading edge of their wings thus giving them lift on both strokes.
Hummers can starve to death in less than an hour, which explains their hyperactivity whenever food, or competitors, are in the area. But they have to sleep part of the time, so how do they live through that? They survive through an extraordinary ability to put their bodies in suspension in a condition known as torpor.
When a hummer takes a break and sits on a branch for a while, its heart beats about 250 times per minute. When it's in torpor, its heart rate drops to 50. But when its flying the tiny heart in the tiny bird beats an amazing 1,250 times per minute. A healthy human's heart beats between 60 and 100 times per minute.
All of those talents allowed the first hummers that reached South America to take up residence throughout the Andes, inhabiting high valleys and low plains, as well as near the top. McGuire speculates they eventually migrated to North America, where we see them today from coast to coast.
Life was probably not easy for those early pilgrims. Some were limited to very small areas, so a change in the weather or use of the land could have been disastrous.
"I suspect there were many extinctions," he said.
But today, their numbers are great, and their ability to adapt to new situations has been well documented, so the number of species will most likely continue to soar, he added.
That's great, because we need these birds, weighing less than an ounce, to keep life challenging for scientists who are still trying to understand their remarkable talents.