sometimes my pokemon make a weird cry after their normal cry. it sounds like rushing wind/ "fwoosh" . It happens with multiple pokemon; pokemon of the same species do not all have it.

in example, my main rookidee has the fwoosh, but my second rookidee from an aura battle does not. here's some more info on the rookidee:

-no ribbons
-no pokerus
-not an aura battle pokemon
-caught on route one
-it started doing this before i even unlocked pokemon camp

everything else is about the same--nothing out of the ordinary. what's up with it? what does it mean?