Thanks, everyone, for all the kind comments!
Chillybean, I had no idea Dragonflies would bite! thanks for the info!
Tarev, this was a young male. I suspect he just wasn't experienced enough to see and know to avoid the web. Thanks for the reminder that the hummers can use spider threads for nest-building. This incident was during the peak of the southern migration so I doubt any birds were still collecting for nests
DavidLMo, I heard from one person that the large spiders can eat the little birds, or at least a portion of them. Too terrible to think about, isn't it?
Sheridragonfly, thank you for the acorn! I, too, wondered whether the spider had bitten the bird.