 All three use flycatching to acquire some or all of their food.But these three families belong to separate branches of the evolutionary tree of songbirds, which diverged in two branching events some 60 and 90 million years ago and continued to evolve independently in different parts of the world.Likewise, the similarities of swifts and swallows once led naturalists to conclude they were related, but it is now established that they are unrelated, and that the same lifestyle has led to the same adaptations.