Not long ago, I heard an interview on NPR with Sally Roth, the author of An Eye on the Sparrow, a book about the symbolism and science of the birds mentioned in Scripture. I can’t find the audio online anymore, but during the conversation Ms. Roth speaks about the pure white dove, which is often used to represent the Holy Spirit. She notes that such a bird is not indigenous to Israel, and that the dove mentioned in Scripture would likely have been its close cousin, the rock dove. In other words: a common pigeon.
Whether or not this is accurate, I don’t know. It seems to me that the Holy Spirit can do whatever He wants, but regardless there is some nice symbolism to be found in either case.
In churches, particularly old ones, pelicans are another common motif. Why? In medieval times, a mother pelican was rumored to be so nurturing and protective of her young that, in times of hardship, she would cut herself with her beak and feed the babies with her own blood. Well, there is no evidence of this at all. Pelicans simply do not do this. But the symbol persists, and it is a magnificent one if we can get past the zoological inaccuracy of it. It is not hard to see why the pelican is an enduring symbol for Our Lady, the Church, and the Passion of Christ.
Photo of pelican stained glass by By Rebecca Kennison – Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=1585228