My parents have a house with many large windows. They put small bird silhouettes on them, which works wonders, but the woman who cleans our windows may take them off again.

the song thrush
many of them, upon returning from winter break, break their necks on my parents' windows - this one hit the window, flew away, then sat upright for half a minute; my dad and I looked at each other, relieved - the next thing I saw of it was my father picking it up. "What happened?" I asked. "It just tumbled over," he said.
the tree sparrow
a flight of some ten tree sparrows passing the house at cruise speed; one of them, inexplicably, makes a right angle hook to crash head on into a window - dead as a doornail
the house sparrow
a strange noise came from the chimney pipe - sure enough, a bird had descended from the chimney and it didn't sound happy. We opened the door to the fireplace, but it was nowhere to be seen. We shut it. The next morning, we found a dead house sparrow behind it, in the ashes. Poor little trapped bird, why couldn't I have saved you ...
the black-headed gull
we were crossing the provincial road, the kind of road you don't like to be next to, when we saw this gull beside the road. It stepped onto the road, and moved on, steadily, deliberately, right in front of a car, which hit and killed it. If this wasn't suicide, what on earth went on inside the brains of that gull?