The speaker looks for a personal anthem, a song that stands for who they are, and finds it in unlikely places. It isn't a grand national tune. It's the rustle of leaves, which the poem calls "discourse" and says is "full of ill humors," as if the trees were grumbling to one another. It's also the complaints of the speaker's old black dog.
The title, "Anti-anthemic," tells us this is a song that rejects pomp. Instead of pride or triumph, the poem offers grumbling, age, and bad moods. Yet the ending turns warm. The dog's call "blessing the blood" suggests something that stirs the body and feels alive, and the phrase "like a true howl" praises its honesty.
The mood is quiet, wry, and earthy. The speaker seems at home with complaint and decay, and even finds them comforting. Real feeling, the poem suggests, comes from the natural world, not from official music.