I know what you're thinking, a bird called a tree swallow must be a truly monstrous bird, gigantic and frightening if it can swallow an entire tree. I mean, come on, how could such a bird even fly? Then again, unlike me, you probably don't have the mind of a three year-old. Trying to photograph a swallow in flight is a formidable challenge, although with the new ultra-fast mirrorless cameras that may be a little more satisfying now. Fortunately swallows need to rest frequently. A fence at the edge of a meadow is a great place for a swallow to rest between long exhaustive aerial forays. If you watch them you might notice what I've noticed, time and time again, a swallow will choose the same perch each time, or at least a similar perch nearby. Another good perching site is next to a proffered domicile. It's so much easier to get a photo if you station yourself accordingly.
Tree Swallow