I thought for some time that the hole that was dug under the fence at the south corner of my yard was a jack-rabbit construction. The cottontails can get through the chain fence, but not the jack-rabbits, so they would need a way of getting in if they wanted to get some water from the bottom half of the birdbath. But I did begin to suspect that hole was rather larger than jack-rabbits needed. I was right.
This morning I saw a coyote walking down the street outside my window. He glanced over at the birdbath and looked at the water level, then continued along the fence out of sight behind the plants. A moment later indeed he reappeared but did not initially go for a drink.
He turned and walked round the house to the west and I lost sight of him – there’s no window on that side of the house. The pigeons, feeding at the back suddenly scattered so I knew he was close. Went back hopefully to the bedroom window and was rewarded. Looks like android movies upload seamlessly to Windows10, so I hope this works for you! I wasn’t able to upload it into my post, but I was able to put it on my website: CoyoteInYard