The two Marsh Wrens who lay claim to the cattails of Southeast Pond have been venturing forth into unknown territory recently. It all started when they ratcheted themselves up the berry tree that grows amid the cattails on the north end of the pond. From there, they could look over a vast spread of prairie, where sparrows and finches have been feasting on the grass seeds and chicory that grew so abundantly this past summer.

Something about the prairie or the other birds must have attracted the wrens, because, after hesitating in the tree a few days, they finally worked up the courage to fly over the Loop Trail that separates the pond from the field, crossing the Rubicon, as it were. Since then, they have roamed all over the field. I hear them chittering among the grass tufts that rise from the prairie like miniature teepees on the Great Plains. If the air is still, I can follow their progress by the twitching of the grass tufts.

Occasionally, one of the wrens will pop up at the top of a grass stem to see what’s what before diving back down again. The marsh that figures so large in their names seems a distant memory to them, at least for now. “Marsh?” they seem to say. “What are you talking about?”

It’s a reminder that although we humans like to give names to everything, thereby categorizing and locking it all into niches, the ones thusly named do not have to agree to stay safely categorized. Marsh Wrens can be prairie wrens whenever they want. And who knows? Maybe they’ll become forest wrens someday, or mountain wrens, or Lexus-driving suburban wrens. Whatever they do, it won’t be up to an outside agency to set their internal limits.

It never was.