Barn Swallows are pretty common since as their name suggests, they frequently nest in human structures, like barns. They can be a bit of a pain to care for since they tend to stop begging as they age, especially when it comes to water. This results in dry skin, which when combined with the special soft cages we keep them in to avoid feather damage, they get DUSTY. If you don't clean their cages out well every time, they'll be piles of bird dandruff wedged in the corners that may get puffed out by the flutter of wingbeats at any moment, ready to get in your eyes and generally make you miserable. Fortuantly, we do a decent enough job keeping them clean that it's more a mild irritation than a literal sandstorm of bird skin. It can be especially difficult if they're a lot of birds in one cage though, as it accumulates faster and they tend to fly around a little more when together. They can be quite amusing interacting with their siblings, one of the funniest things I've witnesses while working (on numerous occasions no less) is a Barn Swallow begging so eagerly that it somehow ends up with its sibling's head in its mouth. They'll also do this to your fingers if you accidentally get your hand too close. Silly little guys.