There were 3 fledgling blue jays in a nest in our front yard tree a few days ago. One of the babies was dangling upside down on the side of the nest. It kept flapping its wings until it righted itself back up only to flip over again and dangle off the side while flapping its wings over and over again until it got tired. It had been dangling from the next for most of the day. My son climbed the tree and saw that this fledgling's foot was all tangled up in twine. He carefully cut off the twine, and the baby jumped out of the nest and fluttered to the ground along with one of its siblings. We could see that the twine was still wound around its leg and had dug into the leg causing it to bleed. I used manicure scissors to gently cut the remaining twine off its leg. We put both babies back in the nest, and the mother continued to feed them. When we woke up the next morning, the baby that had been entangled was dead on the ground under the tree. There were no signs of trauma. It was just dead. What could have happened to it?