I'm pretty sure that its illogical.Boomburst's description says that it attacks everyone with a terrible and explosive sound.How does a tiny swallow Pokemon make a terrible and explosive sound?! But then again birds do sing. Maybe it attacks by singing terribly! But I'm pretty sure thats not the reason.And Pokemon has a lot of illogical things like Tyrantrum with Strong jaw but it only get fang moves by breeding.
Hope I helped!