There's nothing common about hummingbirds.
They are the smallest bird, coming from the smallest egg and living in the smallest nest; their colors include metallic greens, blues and reds; they have the highest metabolism of any animal, with a heartbeat of well over 600 beats per minute; and they are the only group of birds that can deliberately fly backwards.
Their diet consists of flower nectar, sap from trees, spiders and insects, usually captured in or near flowers.
It's been estimated that not one square meter, or 40 inch plot of land, goes unvisited by them in any given year. Still, they may go unnoticed until hummingbird feeders are placed to draw them more readily into focus.
If you've never had the privilege of watching hummingbirds closely or regularly, it is well worth the time and effort to entice them into your garden. You can provide supplemental nourishment with a sugar-water mixture in a hummingbird feeder (4 parts water to 1 part sugar, boiled to remain fresh longer, NOT dyed red and changed frequently during hot weather). Also, a number of plants will attract them into your yard and encourage them to stay longer.
As a rule, native plants contain far more nectar than cultivated hybrids. Some spring-blooming plants for their early migration in late April to mid-May include: azalea, bottlebrush buckeye, columbine, coral bells, coralberry, crabapple, currant, flowering quince, hawthorn, honeysuckle, penstemon, tuliptree and weigela.
For the fall migration that begins in early August and can run almost until frost, there are lots of options. Some of their favorites are: agastache, butterfly bush, daylily, four o-clocks, gayfeather, hibiscus, hollyhock, honeysuckle, hosta, lambs' ears, milkweed, monarda, penstemon, phlox and salvia.
With the addition of a few hummingbird feeders and lots of flowering plants to our yard, we went from seeing one hummingbird a year to seeing them several times a day for several months during their fall migration. And though they are regulars now, "common" they are not.