Mutts from four years ago today needs no explanation ...
Bizarro from today in 2013 is a bit anticipatory, with a bald eagle wearing a toupee very similar to that of the current President:
Strange Brew from one year ago today. Literally speaks for itself.
February 28 the third ... Speed Bump from last year, with the old cliché:
Hagar the Horrible from this date in 2013 features a rather annoying (to him) Polly the parrot:
The second of our February 28 toons is Heathcliff from 2013. I don't quite get the joke, though.
This poignant The Other Coast strip is from five years ago today. Thankfully, Mickaboo birds don't have that problem (as proven by my little flock, which is having its morning flight routine around my apartment as I post this).
The Dogs of C-Kennel from this date in 2013 spins off from a popular smartphone game (has Angry Birds really been around for over four years already?):
Another groaner provided by Frank and Ernest from February 17, 2012:
Another standalone magazine cartoon. As with some previous standalones, I do not know the origin but am guessing based on the caption typeface that it was the New Yorker.