The main foods consumed year round are insects and spiders. During the breeding season, Vaux's swifts soar above the forest canopy and swoop down, pausing at a tree to feed on insects flying near the tree. These swifts are generally spotted soaring above mature forests approximately 20 to 50 meters above the top of the canopy. (Bull, Collins 1993)

During the breeding season, Vaux's swifts feed both in flocks and alone. They capture prey mid-flight. When feeding nestlings, swifts return to the nest with a mouth full of food items. Generally, during the breeding season, these items consisted of flies, hoverflies, ants, bees, planthoppers, aphids, spindlebugs, lanternflies, bark beetles, moths, mayflies, true bugs, and spiders. (Bull, Collins 1993)