"Spring" is humorous, eighteen-line song in which the speaker tells a cautionary tale for all the "married men" in the house.
The poem's first nine-line stanza begins with a very vivid, lush description of blooming flowers and foliage (it is, after all, spring). The scene is almost painterly in its use of color and specific flower forms. But just as we are settling in and starting to enjoy this colorful, lively scene, a pesky, mocking cuckoo bird shows up and kind of puts an unpleasant spin on things. The bird's song ("cuckoo, cuckoo") is "unpleasing to the married ear." Suddenly this idyllic scene turns a little sour. Here's a short version of the reason why this song is so upsetting: cuckoo sounds like cuckold, which is an old term for the husband of an unfaithful wife. Enough said?
The second stanza starts off as pleasantly as the first. This time there are images of shepherds, larks (a much less accusatory bird), and "maidens." Things are looking up again, right? Wrong. That cuckoo shows up once more, putting all kinds of unfortunate ideas into the minds and hearts of married men. In the end, it's tough to enjoy spring with all that cuckoo-ing going on.