Fluttershy is only in the acres to birdwatch. She arrived in Ponyville not too long ago, so it made sense that she would want to birdwatch. And all the best birds were in Sweet Apple Acres. She went every day, just to watch the birds. Only for the birds.
If one of those birds was larger, wingless, orange, and Fluttershy desperately wanted to ask her out maybe one day, well...