In this sequence, we learn that the stork carrying Mrs. Jumbo's baby is running behind schedule.
The entire sequence is animated by Art Babbitt. The acting does not require flashy animation, but what's there demonstrates Babbitt's skill. During shot 1, a flying cycle, the stork's entire body stretches and squashes with the beating of his wings. The wing upstroke takes 12 frames while the downstroke takes 8 frames, giving the downstroke a definite accent that is timed to the music.
The rest of the sequence is all about weight. While we haven't seen the contents of the stork's bundle yet, we suspect that it's Mrs. Jumbo's baby and the way that Babbitt handles the weight of the bundle reinforces our belief. The bundle appears heavy when the stork drops it on the cloud. Babbitt also gets great contrast in timing in shot 3 between the stork's slow scanning of the earth below and his fast lunge to prevent the bundle from falling. That's contrasted with the slow lift, emphasizing the weight of the bundle yet again. The bit is repeated twice within the shot.
Shot 8 is another that's all about weight. For a third time, the stork has to stop the bundle from falling. There is a slow lift. The stork grabs the bundle with this beak, uses his wings to hold the bundle from the bottom and then waddles over to the edge of the cloud. That waddle is a very expressive piece of movement clearly showing how difficult it is to move this bundle. At the clouds edge, the stork leaps, and the weight of the bundle rapdily pulls him downward.