Confessions of a Haiku Translator

In Confessions of a Haiku Translator, David G. Lanoue writes:

Like the frogs of spring, swallows tend to appear in groups, so is it not logical to assume that the Great Buddha has sneezed forth a flock? On the other hand, if Issa's bird is solitary, the feeling in the haiku is more comic, I believe, like the old adage about a mountain laboring to give birth to a mouse. Lacking contextual clues from Issa's diary, we must admit that there could be one swallow, there could be many. Any single translation, either way it goes, is semantically incomplete.