Here's Hummingbird-Spotting 101:
First,though it's a rainy, grey, overcast day, you go to Forest Park to look for the Great Horned Owl babies, which have fledged....

There, you chance upon Mark Glenshaw, who helps you locate the beautiful owlets:

You also photograph him holding up a couple of fallen owl feathers:

At this point, you look up into the grey skies and the rain (you've already squelched your way through water and mud for those owls), and you see this:

"What's that tiny spot high up on the tree!" you think, and concentrate:

The tiny spot looks like a bird...

...and you realize, with a thrill, that this black smudge against a grey sky is, in fact, you very first
RUBY-THROATED HUMMINGBIRD (though in the rain it's a Black Blotch Hummingbird):

Here's a GOOD shot of the Ruby-throated Hummingbird (taken by Danny Brown , who's one of the most helpful people I've met here!):

Much pleased with your sightings of the GHO's and the RTH, you slosh home happily in your sodden shoes.
Update: on the 22nd, I saw another of these beauties at the Muny:

This post is dedicated to another hmmngbird.