Fish and rings. They're like virgin-martyrs and repenting playboys -- very common in the stories of saints. In this one, the Queen of Cadzow (a Scottish town that was renamed Hamilton) asked for help from Kentigern, a sixth century monk and bishop. She had been wrongly suspected of intrigue by her husband; his suspicions were fueled by the disappearance of her ring. Presumably, she had given her lover her ring as a pledge, and after he killed her husband and took over Cadzow, he'd give it back to her at their wedding. Kentigern prayed, and then went fishing in the River Clyde. As he gutted his first catch, he found the ring, of course! The King and Queen were greatly relieved, though no mention of a gratuity or finder's fee was in the story. I guess that's where the sainthood comes in. (Of course, unanswered was the question of how the ring left her finger and got into the fish's belly, but as long as the King was happy, everybody was happy.)
Kentigern's crest (all the best saints have crests) has a tree and a bird on it as well. These both go back to when he was a young monk in the abbey of St. Serf. The spirited young monks were playing and somehow Serf's pet robin got killed. The other lads blamed it on Kentigern; he picked up the bird and prayed. It perked right up and flew to a nearby tree. There's nothing in the record to say that Kentigern was subsequently the fallguy for every mishap in the abbey, but I think it's a safe assumption.
The tree on the crest recalls the time he fell asleep on fire duty. The fire on the hearth burned out, which is the second worst thing that can happen on fire duty. (The first is obviously that the house burns down and they die in their sleep.) Recognizing his error, Kentigern went outside, broke some frozen branches off a hazel tree, put them on the hearth and prayed. The fire was rekindled.
Any old saint can find a ring in a fish. Bernardo Corleone was pretty good at healing animals. But Kentigern could do both and build a fire with frozen wood and faith.