A thump on your window usually means that a bird has crashed
into the glass, sometimes stunning, injuring or even killing
itself in the process. Birds fly into windows for several
reasons. Mostly, they don't see the glass as a solid barrier. Or
a bird that sees its reflection in the window may think it can
fly to where the "other" bird is. Houseplants hanging inside
windows may give a bird the illusion that it can fly into the
plants. To reduce the hazards windows pose for birds: Attach
black silhouettes of flying hawks or strips of opaque tape or
flagging to windows to make the glass visible to birds. Install
screens or lightweight netting in front of windows as a cushion
if birds fly into it. Put up an owl statue or other raptor
statue close to the problem-causing window. Keep your blinds or
curtains closed or partially closed. Move houseplants away from
windows, as these attract birds. Move bird feeders either away
from windows (20 feet or more) or closer to windows (three feet
or closer) to help prevent i