It is widely acknowledged that male hummingbirds love the ladies. Love 'em and leave 'em keeps these boys busy. And, maybe the female hummers are content to nest and raise their 2 babies on their own while the males are out chasing around.
So... it's not surprising that these wild and crazy birds are occasionally attracted to exotic females from other hummingbird species. Idaho records in the last few years have documented the offspring of Calliopes with the other 4 species seen in Idaho: Black-Chinned, Broad-Tailed, Rufous, and Anna's.
In 2013 we banded 3 male Broad-Tailed X Calliope hybrids. (See photo on home page). One bird showed up at our Roundup in 2014, and all three appeared again in 2015. A suspected hybrid showed up at our feeder on May 4th. We are hoping to catch them again this year.
Hybrids are usually spotted because they look unique. Their characteristics are often mid way between the 2 species. This spring I caught a Calliope X Rufous male near Moscow, ID. His throat patch bore some resemblance to a Calliope's in shape, and was an unusual iridescent rose and flaming orange. He was the size of a very large Calliope. The shape of his tail feathers said "Calliope" but they were colored with lots of orange like a Rufous female.