Saint John of Capistrano

Poor Saint John gets associated with the migration of the swallows. How unfortunate to have your life and life's project get linked with the fowl. There is always a back story. He studied law, a civil servant, was married but the marriage was annulled with the wife's permission because as it was never consummated, a priest, a very effective preacher, healer and reformer and ecclesial servant. A disciple of Saint Bernardine of Siena and therefore had a devotion to the Holy Name of Jesus and promoted it. See the Wiki article on Saint John and Catholic encyclopedia article on him is here. A Franciscan hagiographical piece on the saint is noted here. Reading all this I'd say the birds didn't reveal the saint's importance.