More or less repeating what I noted before, and as noted in the
post from Janet Partlow, a window mounted hummingbird
feeder tends to stay unfrozen in this sort of weather, at least in
the daytime. Some heat escapes through any glass pane,
even if double glazed. Also, the window mount feeders have
more surface area running close to and parallel with the glass.
I suspect there is some "greenhouse" effect going on with the
clear feeder body and the window behind it, as well. So far we
have had one small bump of one of the chased hummers
against the window, but no damage to the bird apparent. For
the most part, the birds quickly learn to look for the feeder and
not run in to the glass. So far, ours has frozen at night, but
when I put it back out in the morning it stays unfrozen all day,
so now am taking it in at night.

Today, I also took out a circular feeder to hang up at a corner
of the house and a male landed on the feeder's perch while I
still held the feeder in my hand. I had to wait in the cold for
about three minutes while he tanked up before he would let me
hang the feeder. I suspect by tomorrow they will be fighting
over it before I even get it up.Jerry Broadus
PLS 17660