Considering swallows take mosquitoes, gnats and other tiny insects "on the wing", their maneuverability and avoidance capability is quite high and well known amongst ornithologists around the world. Millions of them can fly together at speeds of roughly 8 meters/second, without bumping into one another. (Of course these are unladen swallows flying south with the sun beating their wings 43 times every second, African and/or European, and in the end it's a simple question of weight ratios
).
Honestly, the odds of being struck by a swallow, be it one or hundreds flying around your Mavic, are vanishingly small. We have examined roosts of thousands of bank and barn swallows while using a Mavic and other quadcopters, stirring up individuals in all directions, and never worry about their incessant buzzing by the craft on all sides. They can bob and weave to catch a single mosquito or wind their way through grassy vegetation. Avoiding a slow-moving Mavic for them is child's play.
