Window Hummingbird Feeders
While any hummingbird feeder is great to have in your yard,
nothing can beat having the hummingbirds fly up to your
window while you are inside. So in addition you to the same
features you want in any hummingbird feeder, you want
something that is either small or made mostly of transparent
materials, so you view is relatively unobstructed.
Of course the tradeoff is that you need color to attract the
birds, with red being a favorite color of hummingbirds, so it
should be part of the feeder, as you won't necessarily want
to put coloring in the
hummingbird food.
Attachment to the Window - It's a good
practice to clean your feeder once or twice a week and you
may be more inclined to do so if it's right in your field of
view, so look a the window mounting scheme. Many window
feeders attach with suction cups, which should be relatively
easy to remove often, but you may be inclined to use a hook
or similar mounting scheme that just sits outside the window
so that you can simply take it down to clean..
Mounting - A shade window is better, as the
sunlight tend to encourage mold growth in the feeder.