These are American Goldfinches, spinis tristis. They don't look very yellow, but it is February, and goldfinches are the only finch to undergo a complete molt. This means they are super bright and yellow in the Summer, and boring and olive colored in the Winter. They like to hang out and feed in groups, like my picture suggests.
I was really hoping these were chicadees, because then I could use a bunch of homonym puns (genuses in the Paridae family are also known as tits or titmice). But, maybe I'll be able to get pictures of that kind of bird another time.