according to this, there’s no physiological restraint on small birds to either walk/run or hop. Moreover, big birds can and do hop but not to the same extent due to it being less efficient for their size.
I assumed it was like kangaroos, which are obligate hoppers on account of not being able to move their respective hind legs independently (although, I was certain there was some exception in one extant kangaroo species, but google is yielding nada).
Also, Elsie and Elmer had a comic book you can read here. I find anthropomorphic animals need a certain amount of abstraction or else the turn from charming to nightmarish.