Apparently there is a theory that humming birds that [sit on the perches of the feeders to drink can get hypothermia][1] and die. My experience says that sometimes they hover and sometimes they sit, it just depends on the humming bird and how many of them are at the feeder at once.

**Is there any evidence to back this up?**


  [1]: https://outdoors.stackexchange.com/a/22061/8794