Sometimes a cellphone is just not a cellphone, as we learn from a NYTimes reader.

As an avid Central Park birder, I'm always on the lookout for the unusual. Recently, after two hours of early-morning birding, I reluctantly headed from the park when my ears caught the sound of a cellphone ringing.

I looked into the bushes where the sound was coming from but saw no one.

Then my eye caught a perky little catbird running through its repertory of bird songs. Knowing that it is a mimic, I listened carefully, trying to pick out the different songs. I heard it imitate a white-throated sparrow, a house finch, a song sparrow, and then the clear ring of a cellphone. My mouth dropped open in disbelief. I listened again and, sure enough, heard the catbird repeat bird song, bird song, cellphone and on and on. The little guy made my day.